New Delhi, India CNN  — 

At least 154 people have died and more than 200 others have been hospitalized after drinking tainted alcohol in India, officials said.

The victims consumed unregulated moonshine, known locally as “country-made liquor” in the northeast state of Assam.

Police raised the death toll from 133 on Monday.

Thirty four people have been arrested for their suspected involvement in the supply of the illegal alcohol. Police said they are questioning others associated with bootlegging in the area.

“It is illicit liquor that was brewed locally. We are still investigating what was the composition and what was mixed in the alcohol,” said Mukesh Agarwal a senior police official in Golaghat district in northeastern Assam state.

Police suspect those who drank the liquor contracted “methyl alcohol poisoning” from “methanol that was added to the mixture,” he added.

The first cases, reported Thursday evening, indicated most victims were tea garden workers, said Manoj Baruah, an official in Jorhat, the other district where cases were reported.

“It is a case of alcohol poisoning, and it has affected a few tea gardens and villages surrounding them in this district,” said Partha Pratim Saikia, a senior police official in Assam.

At least 94 people died in the latest incident involving toxic liquor in India.

Illicit booze is cheaper but can kill

The incident is the latest in India’s long battle to control fake or illegal alcohol, which is affordable and readily available to many impoverished people.

Eighty people died in February in Uttar Pradesh and Uttarakhand states after drinking illegal homemade brew. Eight people were arrested as part of a police investigation into that poisoning, and about 400 liters (105 gallons) of illicit booze was seized.

More than 100 people died from drinking illegal moonshine in 2015 in a Mumbai slum, while the deadliest incident was in 2011, when a batch of country-made liquor killed at least 168 people in the state of West Bengal.

The latest victims have sought medical treatment at a local hospital.

Homemade alcohol is typically brewed in villages before being smuggled into cities, where it sells for about 10 cents a glass – about a third the price of legally brewed liquor.

Illegal liquor can be deadly “when other liquids like rubbing alcohol or methanol are added to the distilled spirit,” enabling sellers to increase the amount of liquid and its potential potency, according to SafeProof, a group that lobbies against counterfeit alcohol.

Country-made liquor often contains toxic methanol, which can make people feel inebriated. However, even a very small amount can be toxic. Methanol poisoning can cause confusion, dizziness, drowsiness, headaches and the inability to coordinate muscle movements.

CNN’s Swati Gupta reported from New Delhi. Jack Guy wrote in London, and Hira Humayun wrote in Atlanta.