diff --git a/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/EnvironmentChip.stories.tsx b/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/EnvironmentChip.stories.tsx
index ff268d8c7..d907a0cdf 100644
--- a/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/EnvironmentChip.stories.tsx
+++ b/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/EnvironmentChip.stories.tsx
@@ -37,3 +37,39 @@ export const Active: Story = {
     isActive: true
   }
 };
+
+export const WithHighCriticalIssues: Story = {
+  args: {
+    environment: mockedEnvironment,
+    isActive: false,
+    issueCounts: {
+      highCriticality: 1,
+      mediumCriticality: 2,
+      lowCriticality: 3
+    }
+  }
+};
+
+export const WithMediumCriticalIssues: Story = {
+  args: {
+    environment: mockedEnvironment,
+    isActive: false,
+    issueCounts: {
+      highCriticality: 0,
+      mediumCriticality: 2,
+      lowCriticality: 3
+    }
+  }
+};
+
+export const WithLowCriticalIssues: Story = {
+  args: {
+    environment: mockedEnvironment,
+    isActive: false,
+    issueCounts: {
+      highCriticality: 0,
+      mediumCriticality: 0,
+      lowCriticality: 3
+    }
+  }
+};
diff --git a/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/index.tsx b/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/index.tsx
index 2c799fc5d..1f4fb4da1 100644
--- a/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/index.tsx
+++ b/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/index.tsx
@@ -1,10 +1,12 @@
 import { EnvironmentIcon } from "../../../../common/EnvironmentIcon";
 import { Tooltip } from "../../../../common/v3/Tooltip";
+import { getMostCriticalIssueCount } from "../getMostCriticalIssueCount";
 import * as s from "./styles";
 import { EnvironmentChipProps } from "./types";
 
 export const EnvironmentChip = ({
   environment,
+  issueCounts,
   onClick,
   isActive
 }: EnvironmentChipProps) => {
@@ -15,14 +17,18 @@ export const EnvironmentChip = ({
   };
 
   const environmentName = environment.name;
+  const count = getMostCriticalIssueCount(issueCounts);
 
   return (
     <Tooltip title={environmentName}>
-      <s.StyledChip isActive={isActive} onClick={handleClick}>
+      <s.StyledChip $isActive={isActive} onClick={handleClick}>
         <s.IconContainer>
           <EnvironmentIcon size={16} environment={environment} />
         </s.IconContainer>
         <s.Name>{environmentName}</s.Name>
+        {count && (
+          <s.Counter $criticality={count.criticality}>{count.count}</s.Counter>
+        )}
       </s.StyledChip>
     </Tooltip>
   );
diff --git a/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/styles.ts b/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/styles.ts
index 6dccb6ea0..2eb8df3dc 100644
--- a/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/styles.ts
+++ b/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/styles.ts
@@ -1,13 +1,15 @@
 import styled, { css } from "styled-components";
+import { footnoteRegularTypography } from "../../../../common/App/typographies";
 import { Chip } from "../../../../common/Chip";
 import { activeStyles } from "../../../../common/Chip/styles";
-import { StyledChipProps } from "./types";
+import { CounterProps, ISSUE_CRITICALITY, StyledChipProps } from "./types";
+
 export const StyledChip = styled(Chip)<StyledChipProps>`
   gap: 4px;
 
-  ${({ isActive }) => (isActive ? activeStyles : "")}
-  ${({ isActive }) =>
-    isActive
+  ${({ $isActive }) => ($isActive ? activeStyles : "")}
+  ${({ $isActive }) =>
+    $isActive
       ? css`
           cursor: initial;
         `
@@ -25,3 +27,33 @@ export const Name = styled.span`
   white-space: nowrap;
   text-overflow: ellipsis;
 `;
+
+export const Counter = styled.div<CounterProps>`
+  ${footnoteRegularTypography}
+
+  height: 16px;
+  display: flex;
+  justify-content: center;
+  padding: 0 4px;
+  color: ${({ theme }) => theme.colors.v3.text.white};
+  border-radius: 2px;
+  margin-left: auto;
+
+  ${({ $criticality }) => {
+    switch ($criticality) {
+      case ISSUE_CRITICALITY.HIGH:
+        return css`
+          background: ${({ theme }) => theme.colors.v3.status.high};
+        `;
+      case ISSUE_CRITICALITY.MEDIUM:
+        return css`
+          background: ${({ theme }) => theme.colors.v3.status.medium};
+        `;
+      case ISSUE_CRITICALITY.LOW:
+      default:
+        return css`
+          background: ${({ theme }) => theme.colors.v3.status.low};
+        `;
+    }
+  }}
+`;
diff --git a/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/types.ts b/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/types.ts
index f97888d8a..9b84265e8 100644
--- a/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/types.ts
+++ b/src/components/Insights/InsightsCatalog/EnvironmentSelector/EnvironmentChip/types.ts
@@ -1,11 +1,25 @@
-import { Environment } from "../../../../common/App/types";
+import {
+  Environment,
+  EnvironmentIssueCounts
+} from "../../../../common/App/types";
+
+export enum ISSUE_CRITICALITY {
+  LOW = 1,
+  MEDIUM = 2,
+  HIGH = 3
+}
 
 export interface EnvironmentChipProps {
   environment: Environment;
   onClick: (environment: string) => void;
   isActive: boolean;
+  issueCounts?: EnvironmentIssueCounts;
 }
 
 export interface StyledChipProps {
-  isActive: boolean;
+  $isActive: boolean;
+}
+
+export interface CounterProps {
+  $criticality: ISSUE_CRITICALITY;
 }
diff --git a/src/components/Insights/InsightsCatalog/EnvironmentSelector/getMostCriticalIssueCount.ts b/src/components/Insights/InsightsCatalog/EnvironmentSelector/getMostCriticalIssueCount.ts
new file mode 100644
index 000000000..0f7d6fe02
--- /dev/null
+++ b/src/components/Insights/InsightsCatalog/EnvironmentSelector/getMostCriticalIssueCount.ts
@@ -0,0 +1,35 @@
+import { EnvironmentIssueCounts } from "../../../common/App/types";
+import { ISSUE_CRITICALITY } from "./EnvironmentChip/types";
+
+export const getMostCriticalIssueCount = (
+  counts?: EnvironmentIssueCounts
+):
+  | {
+      count: number;
+      criticality: ISSUE_CRITICALITY;
+    }
+  | undefined => {
+  if (!counts) {
+    return undefined;
+  }
+
+  if (counts.highCriticality) {
+    return {
+      count: counts.highCriticality,
+      criticality: ISSUE_CRITICALITY.HIGH
+    };
+  }
+
+  if (counts.mediumCriticality) {
+    return {
+      count: counts.mediumCriticality,
+      criticality: ISSUE_CRITICALITY.MEDIUM
+    };
+  }
+
+  if (counts.lowCriticality) {
+    return { count: counts.lowCriticality, criticality: ISSUE_CRITICALITY.LOW };
+  }
+
+  return undefined;
+};
diff --git a/src/components/Insights/InsightsCatalog/EnvironmentSelector/index.tsx b/src/components/Insights/InsightsCatalog/EnvironmentSelector/index.tsx
index 66fb0122e..6e25f73d7 100644
--- a/src/components/Insights/InsightsCatalog/EnvironmentSelector/index.tsx
+++ b/src/components/Insights/InsightsCatalog/EnvironmentSelector/index.tsx
@@ -9,8 +9,9 @@ import { NewButton } from "../../../common/v3/NewButton";
 import { EnvironmentMenu } from "../../../Navigation/EnvironmentBar/EnvironmentMenu";
 import { trackingEvents } from "../../tracking";
 import { EnvironmentChip } from "./EnvironmentChip";
+import { getMostCriticalIssueCount } from "./getMostCriticalIssueCount";
 import * as s from "./styles";
-import { EnvironmentSelectorProps } from "./types";
+import { EnvironmentSelectorProps, SelectorEnvironment } from "./types";
 
 const ENVIRONMENT_CHIP_COUNT = 3;
 
@@ -26,6 +27,35 @@ const getSlidingWindow = <T,>(arr: T[], start: number, length: number) => {
   return result;
 };
 
+const sortEnvironmentsByCriticalIssues = (
+  a: SelectorEnvironment,
+  b: SelectorEnvironment
+) => {
+  const aCount = getMostCriticalIssueCount(a.issueCounts);
+  const bCount = getMostCriticalIssueCount(b.issueCounts);
+
+  if (aCount && !bCount) {
+    return -1;
+  }
+
+  if (!aCount && bCount) {
+    return 1;
+  }
+
+  if (aCount && bCount) {
+    if (aCount.criticality === bCount.criticality) {
+      return (
+        bCount.count - aCount.count ||
+        a.environment.name.localeCompare(b.environment.name)
+      );
+    }
+
+    return bCount.criticality - aCount.criticality;
+  }
+
+  return 0;
+};
+
 export const EnvironmentSelector = ({
   environments
 }: EnvironmentSelectorProps) => {
@@ -33,8 +63,11 @@ export const EnvironmentSelector = ({
   const environment = useGlobalStore.use.environment();
   const [isMenuOpen, setIsMenuOpen] = useState(false);
   const { observe, width } = useDimensions();
+  const sortedEnvironments = environments.sort(
+    sortEnvironmentsByCriticalIssues
+  );
 
-  if (environments.length < 2) {
+  if (sortedEnvironments.length < 2) {
     return null;
   }
 
@@ -70,24 +103,24 @@ export const EnvironmentSelector = ({
     setIsMenuOpen(!isMenuOpen);
   };
 
-  const environmentIndex = environments.findIndex(
-    (x) => x.id === environment?.id
+  const environmentIndex = sortedEnvironments.findIndex(
+    (x) => x.environment.id === environment?.id
   );
 
   const environmentsWithChips =
-    environments.length > ENVIRONMENT_CHIP_COUNT
+    sortedEnvironments.length > ENVIRONMENT_CHIP_COUNT
       ? getSlidingWindow(
-          environments,
+          sortedEnvironments,
           environmentIndex - 1,
           ENVIRONMENT_CHIP_COUNT
         )
-      : environments;
+      : sortedEnvironments;
 
   const renderEnvironmentMenuButton = () => (
     <NewButton
       buttonType={"secondary"}
       onClick={handleEnvironmentMenuButtonClick}
-      label={`+${environments.length - ENVIRONMENT_CHIP_COUNT}`}
+      label={`+${sortedEnvironments.length - ENVIRONMENT_CHIP_COUNT}`}
     />
   );
 
@@ -96,21 +129,22 @@ export const EnvironmentSelector = ({
       <s.EnvironmentsContainer>
         {environmentsWithChips.map((x) => (
           <EnvironmentChip
-            key={x.id}
-            environment={x}
-            isActive={x.id === environment?.id}
+            key={x.environment.id}
+            environment={x.environment}
+            isActive={x.environment.id === environment?.id}
             onClick={handleEnvironmentChipClick}
+            issueCounts={x.issueCounts}
           />
         ))}
       </s.EnvironmentsContainer>
-      {environments.length > ENVIRONMENT_CHIP_COUNT && (
+      {sortedEnvironments.length > ENVIRONMENT_CHIP_COUNT && (
         <>
           {/* // TODO: refactor this to use only popover */}
           {isMenuOpen ? (
             <NewPopover
               content={
                 <EnvironmentMenu
-                  environments={environments}
+                  environments={sortedEnvironments.map((x) => x.environment)}
                   onMenuItemClick={handleMenuItemClick}
                 />
               }
diff --git a/src/components/Insights/InsightsCatalog/EnvironmentSelector/types.ts b/src/components/Insights/InsightsCatalog/EnvironmentSelector/types.ts
index 51a8eb487..53a5eea5e 100644
--- a/src/components/Insights/InsightsCatalog/EnvironmentSelector/types.ts
+++ b/src/components/Insights/InsightsCatalog/EnvironmentSelector/types.ts
@@ -1,5 +1,10 @@
-import { Environment } from "../../../common/App/types";
+import { Environment, EnvironmentIssueCounts } from "../../../common/App/types";
+
+export interface SelectorEnvironment {
+  environment: Environment;
+  issueCounts?: EnvironmentIssueCounts;
+}
 
 export interface EnvironmentSelectorProps {
-  environments: Environment[];
+  environments: SelectorEnvironment[];
 }
diff --git a/src/components/Insights/InsightsCatalog/index.tsx b/src/components/Insights/InsightsCatalog/index.tsx
index b379b4872..af25f3f32 100644
--- a/src/components/Insights/InsightsCatalog/index.tsx
+++ b/src/components/Insights/InsightsCatalog/index.tsx
@@ -31,6 +31,7 @@ import { Tooltip } from "../../common/v3/Tooltip";
 import { IssuesFilter } from "../Issues/IssuesFilter";
 import { trackingEvents } from "../tracking";
 import { EnvironmentSelector } from "./EnvironmentSelector";
+import { SelectorEnvironment } from "./EnvironmentSelector/types";
 import { FilterButton } from "./FilterButton";
 import { FilterPanel } from "./FilterPanel";
 import { InsightsPage } from "./InsightsPage";
@@ -112,6 +113,17 @@ export const InsightsCatalog = ({
     "application"
   );
 
+  const appliedFilterCount =
+    filters.length + (filteredInsightTypes.length > 0 ? 1 : 0);
+
+  const areSpanEnvironmentsEnabled = getFeatureFlagValue(
+    backendInfo,
+    FeatureFlag.ARE_SPAN_ENVIRONMENTS_ENABLED
+  );
+  const selectorEnvironments: SelectorEnvironment[] = areSpanEnvironmentsEnabled
+    ? insightStats?.spanEnvironments ?? []
+    : environments?.map((x) => ({ environment: x })) ?? [];
+
   const handleRegistrationComplete = () => {
     sendUserActionTrackingEvent(
       mainTrackingEvents.PROMOTION_REGISTRATION_FORM_SUBMITTED
@@ -245,15 +257,12 @@ export const InsightsCatalog = ({
     );
   };
 
-  const appliedFilterCount =
-    filters.length + (filteredInsightTypes.length > 0 ? 1 : 0);
-
   return (
     <>
       <s.Toolbar>
         <s.ToolbarRow>
-          {isAtSpan && environments && environments.length > 1 && (
-            <EnvironmentSelector environments={environments} />
+          {isAtSpan && selectorEnvironments.length > 1 && (
+            <EnvironmentSelector environments={selectorEnvironments} />
           )}
           {!isAtSpan && renderFilterPanel()}
           <s.ToolbarButtonsContainer>
diff --git a/src/components/Insights/InsightsCatalog/styles.ts b/src/components/Insights/InsightsCatalog/styles.ts
index 65e03eff3..ccdf32114 100644
--- a/src/components/Insights/InsightsCatalog/styles.ts
+++ b/src/components/Insights/InsightsCatalog/styles.ts
@@ -113,4 +113,5 @@ export const ToolbarButtonsContainer = styled.div`
   display: flex;
   gap: 4px;
   align-items: center;
+  margin-left: auto;
 `;
diff --git a/src/components/Insights/insightTickets/common/useLoading.ts b/src/components/Insights/insightTickets/common/useLoading.ts
index b77d0e505..8c71e4070 100644
--- a/src/components/Insights/insightTickets/common/useLoading.ts
+++ b/src/components/Insights/insightTickets/common/useLoading.ts
@@ -11,9 +11,12 @@ export const useLoading = (
       return;
     }
 
-    const timerId = setTimeout(() => setIsLoading(false), cancelTimeoutMs);
+    const timerId = window.setTimeout(
+      () => setIsLoading(false),
+      cancelTimeoutMs
+    );
     return () => {
-      clearTimeout(timerId);
+      window.clearTimeout(timerId);
     };
   }, []);
 
diff --git a/src/components/Insights/useInsightsData.ts b/src/components/Insights/useInsightsData.ts
index 11004db56..ad61817be 100644
--- a/src/components/Insights/useInsightsData.ts
+++ b/src/components/Insights/useInsightsData.ts
@@ -204,9 +204,8 @@ export const useInsightsData = ({
   }, [getDataListParams, getStatsParams, setIsLoading, isAppReadyToGetData]);
 
   useEffect(() => {
-    const timerId = refreshTimerId.current;
     return () => {
-      window.clearTimeout(timerId);
+      window.clearTimeout(refreshTimerId.current);
     };
   }, []);
 
diff --git a/src/components/common/App/types.ts b/src/components/common/App/types.ts
index 167b1043e..be476acde 100644
--- a/src/components/common/App/types.ts
+++ b/src/components/common/App/types.ts
@@ -54,6 +54,17 @@ export interface ScopeSpan {
   role: "Entry" | "Internal" | "Unknown" | null;
 }
 
+export interface EnvironmentIssueCounts {
+  highCriticality: number;
+  mediumCriticality: number;
+  lowCriticality: number;
+}
+
+export interface SpanEnvironment {
+  environment: Environment;
+  issueCounts: EnvironmentIssueCounts;
+}
+
 export interface Scope {
   span: ScopeSpan | null;
   code: {
@@ -163,6 +174,7 @@ export interface InsightStats {
   unreadInsightsCount: number;
   criticalInsightsCount?: number;
   allIssuesCount?: number;
+  spanEnvironments?: SpanEnvironment[];
 }
 
 export interface UserInfo {
diff --git a/src/featureFlags.ts b/src/featureFlags.ts
index 3b985866a..4d5d167de 100644
--- a/src/featureFlags.ts
+++ b/src/featureFlags.ts
@@ -10,6 +10,7 @@ export const featureFlagMinBackendVersions: Record<FeatureFlag, string> = {
   [FeatureFlag.IS_HIGHLIGHTS_SPAN_INFO_ENABLED]: "0.3.19",
   [FeatureFlag.IS_DURATION_BREAKDOWN_QUANTITY_ENABLED]: "0.3.34",
   [FeatureFlag.ARE_ISSUES_FILTERS_ENABLED]: "0.3.72",
+  [FeatureFlag.ARE_SPAN_ENVIRONMENTS_ENABLED]: "0.3.95",
   [FeatureFlag.IS_REPORT_ENABLED]: "0.3.95"
 };
 
diff --git a/src/hooks/useFetchData.ts b/src/hooks/useFetchData.ts
index ec3e1eefe..909aa555f 100644
--- a/src/hooks/useFetchData.ts
+++ b/src/hooks/useFetchData.ts
@@ -96,7 +96,6 @@ export const useFetchData = <T, K>(
   ]);
 
   useEffect(() => {
-    const timerId = refreshTimerId.current;
     const handleData = (data: unknown, timeStamp: number) => {
       if (isInProgress) {
         if (handleResponse) {
@@ -111,7 +110,7 @@ export const useFetchData = <T, K>(
 
     return () => {
       dispatcher.removeActionListener(responseAction, handleData);
-      window.clearTimeout(timerId);
+      window.clearTimeout(refreshTimerId.current);
     };
   }, [responseAction, isInProgress, handleResponse]);
 
diff --git a/src/types.ts b/src/types.ts
index 98fe0f2cb..596b2ab48 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -12,6 +12,7 @@ export enum FeatureFlag {
   ARE_NEW_INSTRUMENTATION_ATTRIBUTES_ENABLED,
   IS_DURATION_BREAKDOWN_QUANTITY_ENABLED,
   ARE_ISSUES_FILTERS_ENABLED,
+  ARE_SPAN_ENVIRONMENTS_ENABLED,
   IS_REPORT_ENABLED
 }