At least nine people were killed when a three-storey building collapsed in heavy rains in a Mumbai suburb on Sunday, state media reported, and officials said 32 people were killed by lightning a day earlier in India's eastern state of Odisha.
Authorities had already announced a death toll for Saturday of at least 17 people in heavy rains in the northeastern state of Assam.
Lightning also killed 15 people in Bangladesh in the past two days, disaster management officials in Dhaka said on Sunday, adding to a death toll of 17 in flooding on Saturday. About 300 people have died from lightning in Bangladesh so far this year.
Persistent heavy rains this week have caused widespread disruption across South Asia. At least 68 people died in Nepal by flash floods and landslides.
About 50,000 people from southern and eastern India had to be evacuated in recent days as storms pushed water levels to dangerous levels, damaging crops and causing more than 3,000 houses to collapse.
Most of the 32 who died in Odisha were farm laborers killed in a series of lightning strikes. Prime Minister Narendra Modi on Sunday called the deaths "saddening", his office cited him as saying on his official Twitter feed.
In financial hub Mumbai, at least nine people were killed and 20 people were injured in the building collapse, state broadcaster All India Radio said.
Rescue operations were ongoing, the radio station said in a tweet.
Flooding, an annual problem during the monsoon season, has been worsened by crumbling civic infrastructure, clogged drains and uncontrolled urban expansion in a country with a fast-growing population of 1.3 billion.