Dense fog and severe air quality levels have caused travel chaos in India’s capital Delhi.
Visibility in several areas was reported to be zero in the early hours of Friday, disrupting flights, trains and road transport.
More than 150 flights have been delayed and dozens of trains are running behind schedule due to bad weather conditions, reports say.
This is a recurring problem in northern India every winter, where low temperatures between December and January trap pollutants close to the ground – which affects visibility – making travel difficult and the air hazardous.