EcoTwin Delhi PM2.5 Dataset: hourly air quality and meteorology for 37 CPCB stations (2024-2026)

Hourly air-quality and meteorological observations for 37 Central Pollution Control Board (CPCB) monitoring stations in Delhi, India, from 1 January 2024 to 10 April 2026 (737,077 station-hours; 37 stations x 19,921 hours; no missing values after imputation). Variables: PM2.5, PM10, NO2, SO2, CO, O3, relative humidity, ambient temperature, wind speed, wind direction, and derived wind u/v components. The data were cleaned (45 raw station files audited, 8 sparse stations removed, coordinates verified), physically implausible values were masked, and gaps were filled by a tiered imputation procedure. Imputed values are not flagged in the main file; a per-station, per-variable table of original data availability is provided. Supplementary files contain per-station CSVs, reanalysis wind and real forecast wind issued about one day earlier from Open-Meteo for each station, a distance-based station adjacency matrix, and a wind climatology. The dataset supports spatio-temporal PM2.5 forecasting research and accompanies the EcoTwin project (a wind-aware temporal graph convolutional network and digital-twin dashboard). See README.md for column definitions, processing steps and limitations (notably that about 24-29% of humidity, temperature and wind values, and about 24% of SO2 values, are imputed, and that station wind agrees only weakly with reanalysis wind). The underlying observations originate from CPCB, Government of India, and remain subject to CPCB's own terms; the processed and derived material is shared under CC BY 4.0 with attribution.