Chennai woke up to thick smog early on Saturday, the first day of Pongal celebrations. People often celebrate Bhogi Pongal by burning old belongings as a gesture of welcoming new things.
Several flights were delayed in the city, and the air quality index plummeted. At 9.40 am, levels of PM2.5, or particulate matter with a diameter less than 2.5 micrometers, was at 225 in Alandur and 250 in Manali, at 9.40 am.
Visibility reduced to less than 50 metres, The Times of India reported, and more than 10 flights were diverted to other cities. Several flights were also cancelled.
Several Twitter users shared pictures and videos of the smog earlier in the morning: