Methodology

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— OpenCity.in mirrors of ward-level results (2010, 2015); Wikipedia for 2021, as WBSEC’s portal is unavailable
• Real estate— NHB RESIDEX (HPI@Assessment), RBI House Price Index releases
• Employment— Periodic Labour Force Survey (PLFS / MoSPI) annual reports and the Million-plus Cities report
• Energy— Central Electricity Authority (CEA), CESC annual reports
• Digital infrastructure— TRAI Performance Indicator Reports, DARPG CPGRAMS monthly reports (national and West Bengal government)
• Disease— NCVBDC state-wise tables (West Bengal); KMC dengue and malaria counts as reported in the press
• Rainfall & waterlogging— IMD press releases (Alipore), KMC Monsoon Book 2021, WB Irrigation & Waterways Department. No CWC gauge exists for Kolkata.
• Bus routes— WBTC's official city bus route table (government routes); the Kolkata Bus-O-Pedia community catalogue via the calcutta-transport project (private and minibus routes, which have no official published list); OpenStreetMap route lines. Each route is labelled Official, Community or OpenStreetMap. No timings or fares are shown.
• Judiciary— NJDG figures via Rajya Sabha answers (West Bengal state-wide), India Justice Report 2022/2025, Calcutta High Court statements
• Wetlands & green space— Ramsar Information Sheet, Yadav et al. 2024, Paul & Bardhan 2022
• 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

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 appears in the main national ranking once (2023: 438th of 446 cities above 1 lakh). MoHUA reports record the West Bengal state opting out in 2019, 2020 and 2022; 2024–25 has no West Bengal city in the main rankings. Rankings use different population categories and maximum scores each year.
• IMD temperature CSVs— contain “Tr” (trace rain) and dashes for missing values; cleaned with pandas’ coercion before aggregation.
• Warming-trend slope— the 0.033°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 (wbsec.gov.in) has been unreachable. 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.