The toll in West Bengal due to heavy rain and floods crossed 50 on Sunday, after at least nine more deaths, including that of four children, were reported from different districts. The four children were killed and four other people seriously injured when they were struck by lightning in Basithat in North 24 Parganas district on Sunday, police said.

Buildings with weak structures collapsed in many places, including in Kolkata, following overnight downpour.

While two people were killed in a building collapse in Katwa in Burdwan district, an elderly man was crushed to death after a portion of his house collapsed in Kolkata. A two-year-old was killed in Murshidabad district when a wall collapsed. A similar death was reported in Bankura district.

Chief Minister Mamata Banerjee met officials and postponed her upcoming tour of north Bengal. "Over 12 districts have been hit and over 36 lakh people affected by the heavy rainfall. Till today, 71 mm of rainfall has been recorded. The release of water by the neighbouring states like Odisha and Jharkhand has only compounded the problem," Banerjee said after meeting officials.

The Chief Minister said Murshidabad, Hooghly, Burdwan, Howrah were the worst affected districts. She assured that top government and police officials were deputed to supervise relief and rescue work.

Banerjee said that besides 47 municipalities, 210 blocks and 9,691 villages were affected by the flood due to heavy rains triggered by Cyclone Komen.

Crops in over 2.1 lakh hectares of land were destroyed across the state, she said. "While the entire state administration is working to reach out to the affected, we urge all political parties and NGOs to assist in relief work," she said.

After many parts of the state capital got waterlogged, the Kolkata Municipal Corporation pressed into service over 300 pumps to drain out the rainwater. Places like Mukundpur, Dum Dum Park and Alipore Bodyguard Lines remain inundated, as people used boats to ferry across.

Railway tracks under the Eastern Railway continued to be submerged in some areas, while airport runways also remained inundated for the second consecutive day.

Meanwhile, the regional meteorological office has forecast heavy to very heavy rain at a few places in the Gangetic and sub-Himalayan West Bengal till Tuesday. Fishermen have been warned not to venture out into the sea on the West Bengal coast.

President Pranab Mukherjee, in individual messages to the governors of the flood-affected states including West Bengal, condoled the loss of lives due to Cyclone Komen and the floods.