Here's your 10-point cheat-sheet to this big story:
The weather office has forecast more rain in Punjab, Haryana and Himachal Pradesh. In Punjab, the worst affected districts include Pathankot, Ropar and Ludhiana.
Punjab Chief Minister Captain Amarinder Singh has declared it a "natural calamity" and allocated Rs 100 crore for floo-hit districts.
In Delhi, the water level in the Yamuna has risen to 205.94 metres, above the danger mark of 205.3 metres.
Over 10,000 people were evacuated from low-lying areas in the national capital. A Delhi government official said the water level is expected to rise further as Haryana has released a large amount of water from a barrage on Monday.
Indian Air Force helicopters carried dramatic rescue operations in Jammu and Karnal districts on Monday.
Cloudbursts have wreaked havoc at dozens of villages in Uttarakhand's Uttarkashi district, washing away homes and damaging farm land.
The Kailash Mansarovar yatra through via the Lipulekh route was stopped due to landslides. Pithoragarh district magistrate VK Jogdande said the 17th batch of 56 pilgrims was called back to Dharchula base camp.
Most rivers in Uttarakhand are overflowing, with the Ganga crossing the danger mark in Haridwar and flowing close to it in Rishikesh.
In Jammu, an Air Force helicopter rescued four fishermen who were stuck in Tawi river, officials said. They were stranded on a concrete platform at the bottom of a pillar of a structure.
With the weather office predicting heavy rain in parts of Uttarakhand, some schools and anganwadi centres in nine districts have been closed.