Both Delhi and Gurgaon traffic police departments issued traffic advisories.
It is again raining in Gurgaon, visibility is poor. Please drive carefully, switch on the headlights and maintain lane discipline.- Gurgaon Police (@gurgaonpolice) September 1, 2016
Delhi Police also issued a warning for commuters after a part of the pedestrian walkway on the capital's arterial Ashoka Road near India Gate caved in.
Traffic will remain heavy from Ring Road towards Bhairon Road (both carriageways) due to water logging.- Delhi Traffic Police (@dtptraffic) September 1, 2016
Heavy rain in Delhi and Gurgaon had slowed traffic during rush hour as the sky darkened and roads were flooded within seconds.
Massive jams were reported from major roads in Delhi and between the capital and Gurgaon, where the police had warned people early in a tweet to be "patient and disciplined" and "stick to lanes".
US Secretary of State John Kerry, whose visits to religious sites in Delhi were cancelled, joked at IIT: "You guys deserve an award for getting here today. I don't know if you guys came in boats or amphibious vehicles of some kind but I salute you". Mr Kerry was caught in traffic also on Monday, when he arrived to jammed roads from the airport to Delhi.