KOLKATA (AFP) - A batch of home-brewed liquor thought to have been laced with the highly toxic chemical methanol has killed 143 people in eastern India, an official told AFP on Thursday. Hospitals near the impoverished district 30 kilometres (20 miles) south of West Bengal state capital Kolkata have been overwhelmed by victims, either unconscious or complaining of abdominal pains and burning in their chests. Many of them were labourers and rickshaw drivers too poor to afford branded alcohol who stopped for a drink at illegal bars or bought from bootleggers after work on Tuesday. "The death toll has reached 143," West Bengal health services director Shyamapada Basak told AFP, adding that police had arrested 10 people during an investigation into the tragedy in the South 24-Parganas district. More than 100 other victims were still in hospital, including a 12-year-old boy who apparently mistook the liquor for water, hospital authorities said. Bootleg liquor is widely consumed across India and is available in the affected area near the border with Bangladesh for as little as six rupees (11 US cents) for a half-litre, a local resident told AFP. Methanol -- a type of industrial-strength alcohol used as anti-freeze or fuel -- has been found in the remains of 20 of the victims examined by doctors, leading to suspicion that the chemical is to blame. It is sometimes added to "moonshine" in small quantities to increase the alcohol content, but it can cause blindness, liver damage and be fatal.