India, Dec. 16 -- Dense to very dense fog across south Haryana on Monday morning triggered multiple fatal accidents and major highway pileups, leaving at least four people dead and more than 30 injured, while Gurugram witnessed traffic chaos and several non-fatal crashes as visibility dropped to as low as 10 metres in some stretches.

The deadliest incident occurred around 7.30am on the Delhi-Mumbai Expressway in Nuh, where at least 18 vehicles were involved in a massive pile-up on the carriageway towards Delhi. National Highways Authority of India (NHAI) officials said the chain reaction began when a passenger bus rammed into a dumper truck amid near-zero visibility. A car then hit the bus, followed by multiple heavy vehicles crashing in...