India air quality map (PM2.5)
India is home to some of the most polluted air on Earth, and this view centres on it. The map shows PM2.5, fine particles smaller than 2.5 micrometres, near the surface in micrograms per cubic metre, forecast by the NOAA GEFS-Aerosols model.
The pattern to look for is a broad band of dense colour across the Indo-Gangetic Plain, from Punjab and Delhi through Uttar Pradesh and Bihar to Bangladesh. The Himalayas on the north side and a shallow layer of cool air near the ground trap the particles, especially in winter.
Seasons change the picture. From October to November smoke from crop burning in the north-west adds to city emissions. In spring, dust from the Thar Desert and the Arabian Peninsula adds more particles. In the summer monsoon, heavy rain washes the air and the map clears.
The model works on a coarse grid, so it shows regional haze rather than the level on a single street, which can differ a lot. Press play to see 48 hours in steps of 3 hours, and switch on Wind to understand where the haze is travelling.