Officials say at least 40 people have died and hundreds of thousands have been evacuated as floods hit vast swathes of central and eastern India.

Disaster management officials said Monday that days of heavy rain have caused the Ganges River and its tributaries to rise above the danger mark during the last 48 hours in some 20 districts of the states of Madhya Pradesh, Bihar and Uttar Pradesh.

They said at least 17 people died in Madhya Pradesh, 14 in Bihar and nine in Uttar Pradesh from drowning, electrocution and injuries from house collapses.

Floods occur in many parts of India during the monsoon season, which runs from June through September.