Nearly 17 people have died in Assam while at least 14 people have been killed in Bangladesh due to heavy rainfall and floods, officials said on Saturday.
The officials said although rainfall had decreased in the north-eastern state of Assam as of Saturday but millions of people have been displaced as the water levels across rivers were still overflowing.
"Overflowing rivers are flooding new areas, making things worse," said Keshab Mahanta, Assam's water resource minister.
Rajnath Singh, the Interior Minister of India was due to visit Assam and make an aerial survey on Saturday. He is supposed to hold meetings with state officials to discuss relief efforts.
A senior official of the Assam disaster management authority said they have opened more than 800 temporary shelters and centres for food and medicine distribution across the state.
Persistent heavy rainfall also affected many places across South Asia this week. At least 68 people were killed in Nepal by flash floods and landslides.
During monsoon season, flooding is an annual problem in South Asia. This issue has been worsened by crumbling civic infrastructure, clogged drains and uncontrolled urban expansion.