“Every chart links back to a source. Every limitation is called out.”
Methodology
Where the data comes from, how it's processed, and how to cite it.
The standard
Every chart on this dashboard ties back to a specific source and survey year. Every meaningful limitation — stale year, partial coverage, curated extraction — is called out in the chart caption or in the list below. The underlying data is open under CC-BY-4.0; the code is open under Apache-2.0.
Data sources
30+ verified primary sources, grouped by domain:
- People & demographics— Census of India 2011 (RGI), WorldPop 2025 estimates
- Climate & weather— India Meteorological Department (IMD), Open-Meteo Archive API
- Air quality— Central Pollution Control Board (CPCB), Open-Meteo Air Quality API
- Health— National Family Health Survey (NFHS-5, 2019–21), WB Department of Health & Family Welfare
- Education— UDISE+ (Unified District Information System for Education) 2023–24
- Crime & safety— National Crime Records Bureau (NCRB), curated from official PDFs
- Transport— Metro Railway Kolkata, Ministry of Road Transport & Highways (MoRTH)
- Governance— Kolkata Municipal Corporation (KMC) budget documents
- Livability— Swachh Survekshan rankings (Ministry of Housing & Urban Affairs)
- Elections— West Bengal State Election Commission (WBSEC), Wikipedia (where WBSEC data unavailable)
- Real estate— RBI House Price Index, NHB RESIDEX
- Employment— Periodic Labour Force Survey (PLFS / MoSPI), e-Shram registrations
- Energy— Central Electricity Authority (CEA), CESC annual reports
- Digital infrastructure— TRAI quarterly telecom reports, CPGRAMS grievance redressal
- Disease surveillance— IDSP (Integrated Disease Surveillance Programme), NVBDCP (vector-borne disease control)
- Water & flooding— Central Water Commission (CWC) gauge data, KMC monsoon reports
- Judiciary— National Judicial Data Grid (NJDG)
- Land use— ISRO / Copernicus satellite land-cover classification
- Aggregator mirror — OpenCity.in (used where original sources are PDF-only or behind broken portals)
The pipeline
Python downloaders fetch from APIs, OpenCity.in mirrors, and official PDFs. Transforms clean and aggregate the raw inputs into compact JSON files committed to the repo. Next.js bundles those JSONs into the static build at deploy time, so every chart is served as pre-rendered HTML with the data inlined — no runtime database, no API roundtrip, no rate limits.
A daily GitHub Actions cron at 00:30 UTC re-fetches weather and AQI from Open-Meteo, regenerates the relevant JSONs, commits if anything changed, and Vercel auto-redeploys. Other domains refresh on event-driven or release-driven cadences (e.g. when a new NCRB year is published).
Refresh cadence
| Cadence | Domains |
|---|---|
| Daily | Weather, AQI (Open-Meteo) |
| Weekly | CPCB AQI snapshot |
| Per release | Education (UDISE+ annual), Healthcare (NFHS rounds), Real estate (RBI quarterly), Employment (PLFS annual), Energy (CEA annual) |
| Per event | Elections, KMC budget |
| Decadal / unchanged | Census 2011 demographics (next census not yet conducted) |
Known limitations
- NCRB crime data— published as PDFs only; values are extracted and curated by hand. Latest available year is 2023.
- KMC budget— published as PDFs only; revenue and expenditure figures are curated from official summary tables.
- Swachh Survekshan— Kolkata is genuinely absent from all rankings 2020–2025 because KMC did not participate. Not a data error.
- IMD temperature CSVs— contain “Tr” (trace rain) and dashes for missing values; cleaned with pandas’ coercion before aggregation.
- Warming-trend slope— the 0.032°C/decade figure uses full-year data only. Partial years are excluded from the linear regression to avoid seasonal bias.
- Road accident gaps— West Bengal state-level injury counts are missing for 2021–2023 (MoRTH released only accidents and deaths, not injuries, for those years).
- KMC Elections 2021— WBSEC’s portal returns HTTP 503 with an expired SSL certificate. 2021 ward-level results are sourced from Wikipedia and flagged with
data_source: "wikipedia"in the JSON. Turnout and electors are not available from this source. - KMC Elections 2018— no election was held. The OpenCity “2018” CSV is a mid-term councillor directory, not poll results.
License & attribution
Code: Apache-2.0 · Data: CC-BY-4.0. Reuse is welcome with attribution to the dashboard and the original source listed under each chart.
How to cite
For a paper, blog post, or report, use a citation in this form:
Chakraborty, A. (2026). Kolkata City Dashboard. https://kolkata.datacarta.in. Accessed [date].
When citing a specific chart, include the chart title and the underlying source listed beneath it.
Embed this page
Drop these charts into your blog, brief, or report. Updates flow through automatically.