Police say the death toll from drinking tainted liquor in a slum in India's financial hub of Mumbai this week has climbed to 84 in the worst incident of its kind in more than a decade.

Deputy Commissioner Dhananjay Kulkarni says another 31 people were being treated in hospital after drinking the cheap liquor in Malad area in northern Mumbai on Wednesday night. They fell sick immediately.

Kulkarni said Saturday the police have arrested five people who transported and sold the tainted liquor to poor workers.

In 2004, 104 people had died after drinking spurious liquor in Mumbai's Vikhroli area.

Deaths from illegally brewed alcohol are common in India because the poor cannot afford licensed liquor. Illicit liquor is often spiked with chemicals such as pesticides to increase its potency.