Scores of people drank the liquor early last week, most of them poor residents of a Mumbai slum called Malvani, willing to pay for a bottle of cheaply made moonshine that could have contained any number of illegal additives because it cost almost nothing.

By Wednesday, dozens had fallen ill. By Thursday, people were dying. By early Monday morning, nearly 100 had been declared dead from drinking tainted alcohol in what some reporters referred to as “Mumbai’s hooch tragedy.”

The incident, which police say has killed 98 people so far, is the latest in a number of alcohol poisonings in the country. According to the World Health Organization, more than 1,300 people died from methanol poisoning in India between 2001 and 2012. Methanol, a highly toxic anti-freeze valued for its potency and low cost, is often added to bootleg liquor. The mixture is then sold for as little as $1 a bottle to people who can’t afford legal alcohol.

According to NDTV, one of India’s largest broadcast news channels, seven people have been arrested for distributing and selling the liquor and, according to the Associated Press, eight police officers suspended for “negligence” in allowing the transactions to take place on their watch. Meanwhile, authorities have ordered an investigation into whether this particular batch contained methanol.

The incident is Mumbai’s worst in more than a decade — in 2004, 104 people were killed after drinking illicit liquor in the Mumbai suburb of Vikrohli, according to the Associated Press.

But most similar incidents happen in rural areas, Agence France-Presse said. In January, 31 died after drinking illegally brewed alcohol at a cricket match in a village on the outskirts of the northern city of Lucknow. Four years before that, hospitals in West Bengal were flooded with patients who had drunk methanol-laced moonshine, most of them poor day laborers and rickshaw drivers, according to a 2011 report by AFP.

“Enforcement is very weak,” Johnson Edayaranmulah, executive director of the lobby group Indian Alcohol Policy Alliance, told the news agency at the time. “There is an unholy nexus between the authorities — police, excise, politicians — and the bootleggers.”

In Mumbai, more than 100 women — many of them the wives and widows of those affected — are working with police to combat the sale of illegal liquor, NDTV reported. The women told officers where their husbands drink, leading to 36 raids and 22 arrests, according to the network.

Police are also conducting a house-to-house search for other potential victims, according to NDTV, and a “massive manhunt” is underway for the group of bootleggers believed to be the “kingpins” of the illicit alcohol trade.