At least 70 people have been killed in floods in three states, Bengal, Odisha and Manipur, even as the depression created by Cyclone Komen reached Gangetic West Bengal.
Reports, meanwhile, said a flash flood has destroyed a village in Leh in Jammu and Kashmir .
In West Bengal, incessant rain submerged large parts of Kolkata and 12 adjacent districts. High alert has been sounded in five of the districts and people have been asked to leave their homes for the next two-three days.
Chief minister Mamata Banerjee spent Sunday night in office monitoring the flood situation in the state in the aftermath of Cyclone Komen, which hit large parts of Bengal, Odisha and Manipur.
More than two lakh people are in relief camps across 12 districts in the state. Farmland of over 2.1 million hectare has been submerged.
Rain is expected to continue and heavy downpour has been forecast for the next 24 hours, although the intensity is expected to reduce over time.
The flood situation has been worsened by water release from Jharkhand and the Damodar Valley Corporation, Banerjee said.
"DVC is doing business in Bengal. We love them but they can drown Bengal," she said.
Manipur is seeing its worst floods in 200 years, with an estimated one lakh people affected by rising water levels. The situation has improved overall, although the government needs to keep vigil.
Capital Imphal has been cut off from Moreh on the Indo-Myanmar border and Jiribam on the Assam border. Rescue teams are facing a tough time in carrying out operations in Joumol village in Chandel district, where 20 people died in a landslide on Saturday.
A large portion of Thoubal, Bishnupur, Imphal West, Chandel, Imphal East and Churachandpur districts have come under flood waters in Manipur, an Irrigation and Flood Control Department (IFCD) official said.
Three persons are reported to have drowned in last three days while thousands have been rendered homeless by the flood in the state.
Flood waters submerged parts of Imphal West district as well as Uripok, Sagolband, Lamphel, some portion of Kwairamban bazar yesterday, sources said, adding that water level on all major rivers in Manipur is, however, receding as rains stopped since yesterday.
The Chakpi and other rivers in the area are flowing well over the danger mark. Six bridges constructed on the Chakpi river were washed away by turbulent water in Manipur's Chandel district yesterday, they said.
National Disaster Relief teams have been rushed to Imphal from Guwahati. They will be airlifted to Chandel district.
In Odisha, almost five lakh people are in relief camps. The overall flood situation has improved and water in the three major rivers is receding.
In Jharkhand, incessant rain in Giridih and Chatra districts has led to inundation in low lying areas. Rivers in the district are flowing above or very close to the danger mark.