---
title: "Rank asset-level emission sources by emissions"
method: GET
path: "/api/v1/environment/ct/sources"
tags: ["Environment"]
---

# Rank asset-level emission sources by emissions

`GET /api/v1/environment/ct/sources`

List asset-level emission sources (power plants, refineries, cement kilns, steel mills, shipping vessels, aviation, forestry flux, and more) filtered by year, gas, sector, subsector, admin area, city, country group, continent, or owner entities. Results are ranked by reported emissions. Use `/sources/{source_id}` for a single-asset drill-down with monthly time series. Data sourced from Climate TRACE under CC BY 4.0.

## Query parameters

- `year` integer — Calendar year of the emissions snapshot. Inventory covers 2015 through the current year.
- `gas` string — Gas identifier from /definitions/gases.
- `sectors` string, nullable — Comma-separated sector slugs. Use `all_no_forest` to exclude forestry-and-land-use.
- `subsectors` string, nullable — Comma-separated subsector slugs.
- `gadm_id` string, nullable — GADM administrative area identifier restricting results to that area.
- `city_id` string, nullable — GHS Functional Urban Area identifier (e.g. `ghs-fua_2702`).
- `country_group` string, nullable — Named country group slug (e.g. `g7`, `g20`, `eu`).
- `continent` string, nullable — Continent name restricting the result set.
- `owner_ids` string, nullable — Comma-separated owner identifiers (e.g. `E100000001213`) from /owners to restrict to company-owned sources.
- `limit` integer — Maximum rows per page (1 to 1000).
- `offset` integer — Offset into the ranked result set.

## Response `200`

Ranked asset-level source rows with centroid, activity, capacity, and emissions totals.

- EnvelopeCtSourcesListPayload
  - `data` CtSourcesListPayload, required — Response payload for `/environment/ct/sources`.
    - `sources` CtSourceSummary[], required — Asset-level source rows ranked by emissions for the requested filters.
      - `id` integer, nullable — Numeric source identifier assigned by Climate TRACE.
      - `name` string, nullable — Display name of the source (e.g. `Vindhyachal power station`).
      - `sector` string, nullable — Top-level sector slug (one of 10 values such as `power`, `manufacturing`).
      - `subsector` string, nullable — Subsector slug (one of 70 values such as `electricity-generation`, `cement`).
      - `country` string, nullable — ISO 3166-1 alpha-3 country code where the source is located.
      - `adminId` string, nullable — GADM administrative area identifier at the finest reported level.
      - `cityId` string, nullable — GHS Functional Urban Area identifier when the source sits inside one.
      - `assetType` string, nullable — Physical asset type (e.g. `coal`, `gas`, `oil`, `cement-kiln`, `aluminum-smelter`).
      - `sourceType` string, nullable — Observation geometry of the source (`point-source`, `area-source`, `line-source`).
      - `centroid` CtCentroid — Geographic centroid of a source in EPSG:4326 (WGS84).
        - `longitude` number, nullable — Longitude in decimal degrees (EPSG:4326 / WGS84).
        - `latitude` number, nullable — Latitude in decimal degrees (EPSG:4326 / WGS84).
        - `srid` integer, nullable — Spatial reference identifier. Always 4326 for WGS84 lon/lat.
      - `gas` string, nullable — Gas identifier that the reported `emissionsQuantity` refers to.
      - `emissionsQuantity` number, nullable — Total emissions for the queried year in tonnes of the reported gas.
      - `emissionsFactor` number, nullable — Emissions per unit of activity (tonnes of gas per unit of `activity`).
      - `emissionsFactorUnits` string, nullable — Denominator units for the emissions factor. Value may be `license restricted` for commercial-source subsectors.
      - `activity` number, nullable — Observed activity volume over the year (e.g. MWh generated, tonnes cement, kilometres sailed).
      - `activityUnits` string, nullable — Units for the `activity` value. May be `license restricted` for some oil-and-gas subsectors.
      - `capacity` number, nullable — Nameplate capacity of the asset (e.g. MW for power plants, tonnes-per-year for cement).
      - `capacityUnits` string, nullable — Units for the `capacity` value.
      - `capacityFactor` number, nullable — Capacity factor or utilization ratio, when published by the upstream data lead.
      - `year` integer, nullable — Calendar year the emissions row applies to.
    - `limit` integer, nullable — Echo of the request `limit` parameter.
    - `offset` integer, nullable — Echo of the request `offset` parameter.
  - `meta` SugraMeta, required — Metadata on a /api/v1/* response envelope built through `helpers.response.sugra_response`, which is how routes are expected to answer. A route that assembles its own `meta` dict carries only the keys it writes itself, so an optional field below can be absent because this response has nothing to report OR because that route does not build its envelope here - the two are not distinguishable from the outside (API-43).
    - `endpoint` string, required — Requested endpoint path.
    - `data_time` string, required — ISO 8601 timestamp the data on this response is stamped with. It is the source's own timestamp whenever the source supplied one this API could read; when it did not, this field falls back to the value of `response_time` and `data_age_days` is omitted, so the PRESENCE of that field is the signal to read - with the one exception named in its own description, a route that substitutes its own current time for a source timestamp it never received. Usually UTC (`Z`), but a source stating its own numeric offset keeps it (2026-04-16T14:30:00+09:00) rather than being converted a second time. For a source that publishes by period this is the period's START (see `period`) and for one that publishes by calendar day it is that day's midnight - in neither case a moment at which anything was observed or released.
    - `response_time` string, required — ISO 8601 UTC timestamp when this response was produced.
    - `provider` string, required — API name and version.
    - `data_age_days` number, nullable — Age of the data in days at the moment this response was produced, i.e. `response_time` minus `data_time`. Present ONLY when the timestamp this response is stamped with is a clock time that could be read as a real instant. It is ABSENT - never 0 - in every other case. Absent when no readable source timestamp was supplied, because `data_time` then repeats `response_time` and a zero age would assert that the data is current precisely where its true age is unknown. Absent when the source names a calendar day, a month, a quarter or a year (see `period`): the instant is then a boundary this API anchored at midnight, and time since a day or a quarter BEGAN is a different quantity from the age of the data - a daily series is out by up to a day, a quarterly one by up to a quarter. A midnight counts as such a boundary whichever zone it is stated in, and whether the source stated it or this API anchored it. The one case this field cannot see is a route that substitutes its own current time for a source timestamp it never received: the substituted value is a real, readable instant and is indistinguishable from one the source stated, so the age reads as roughly 0. The shared cache-and-fetch helper behind most routes stopped doing that (API-43), but the presence of this field is a statement about the timestamp the response carries, not a guarantee about the route that supplied it. Rounded to 0.001 day (86.4 seconds), so 0.0 is a real measured age anywhere within roughly +/-43 seconds and not a stand-in for unknown; a source stamping an instant in the future reports a negative value (-0.001 or less) rather than being clamped. Sources publish on very different cadences, so a non-zero age is normal, not an error. Preserve absence in client code: a generated client that materialises a missing optional number as its numeric default turns 'age unknown' back into 'age zero', which is the exact confusion this field exists to remove.
    - `source` string, nullable — Identifier of the primary upstream source used for this response.
    - `attribution` string, nullable — Human-readable attribution mandated by an upstream source (e.g. a securities regulator or self-regulatory organization). Present only on responses whose source requires the owner and source to be clearly identified. Do not remove or alter it when using the response.
    - `fallback_used` boolean, nullable — True when the primary source failed and a fallback produced the data.
    - `fallback_chain` string[], nullable — Ordered list of sources attempted, in the order they were tried.
    - `cached` boolean, nullable — True when this response was served from the internal cache.
    - `stale` boolean, nullable — True when the cached response was returned after the upstream rate-limited or errored. Clients can use this to detect degraded data.
    - `period` string, nullable — Unit of observation, when the source publishes by period rather than by instant. `data_time` carries the period's START instant so it stays machine-readable; this field preserves what that instant used to mean, which the conversion would otherwise erase. Present only for such sources, and only when the source hands the API the label itself - a client that converts the period to its start instant before building the envelope loses the label, though not the age exclusion, which is decided by the instant. Note that `data_age_days` is omitted whenever this is present, because an age measured from a period start is not a freshness figure.
    - `notes` string, nullable — Data-quality caveat about THIS response - how old the underlying report is, a chokepoint AIS lower-bound, or that a source-reported `data_time` could not be read and the response time is shown instead. Distinct from `attribution`, which is a licensing obligation. Multiple caveats are joined with ' | '. Present only when there is one.

## Other responses

- `401` — Missing or invalid `x-api-key` header. JSON body with a stable `code` distinguishing `missing_api_key` (no header sent) from `invalid_api_key` (header sent, key not accepted); any other 401 source carries the generic `unauthorized` with its detail as `reason`. Plus `hint`. `plan` is always null on 401 - an unauthenticated request has no plan; quota exhaustion is 429, not 401.
- `422` — Validation Error
- `429` — Daily rate limit exceeded. Check `X-RateLimit-Reset` for the next window.
- `503` — Upstream source is temporarily unavailable. Retry after a short delay.

## Changes

- **2026-09-01** `328d061c12ca` — 3 info
  - added the optional property `meta/data_age_days` to the response with the `200` status
  - added the optional property `meta/notes` to the response with the `200` status
  - added the optional property `meta/period` to the response with the `200` status
- **2026-08-08** `4c4530760ba1` — 12 info
  - added the optional property `code` to the response with the `401` status
  - added the optional property `code` to the response with the `429` status
  - added the optional property `code` to the response with the `503` status
  - added the optional property `hint` to the response with the `401` status
  - …8 more

[Change history](https://skmtc.dev/sugra/apis/sugra-api/changes/api/v1/environment/ct/sources/get.md)

---

[API](https://skmtc.dev/sugra/apis/sugra-api.md) · [All operations](https://skmtc.dev/sugra/apis/sugra-api/llms.txt) · [OpenAPI document](https://skmtc.dev/sugra/apis/sugra-api/revisions/85caa556892f?raw)