India's capital has banned chewing tobacco in an effort to lower the high incidence of mouth and throat cancers.

The Delhi government ordered the prohibition of the sale, purchase and possession of all forms of chewable tobacco, saying violators can be imprisoned for up to six months and fined up to 300,000 rupees (£3,179).

Chewable tobacco products reportedly cause 90% of all mouth cancers in India. Tobacco manufacturers won a court stay against earlier bans, but public awareness about the risks has grown and the Delhi government has vowed to enforce the new ban, which was welcomed by health activists and doctors after it was announced last week.

The tobacco leaves are typically mixed with lime and betel nut, a mild natural stimulant that produces a bright red juice and has been used for centuries across the South Asian continent. Indians place the concoction inside their mouths for an extended period, increasing their oral cancer risk. Tobacco bits, perfumed betel nut powder and flavouring are sold in small plastic pouches, making it easy to carry and consume.

Delhi's health minister Satyendra Jain told reporters that the government has ordered police teams to conduct surprise checks on shops and retail outlets to ensure that the ban is strictly enforced.

Health activists say the number of oral cancer deaths caused by chewing tobacco is alarmingly high.

"This is a positive step by the government and we welcome it. The use of chewing tobacco is so widespread that India is often referred to as the oral cancer capital of the world," said GR Khatri, president of the South Asia chapter of the World Lung Foundation.

Officials say around one million Indians die every year in the country due to diseases caused by tobacco consumption.

Khatri, who has for decades been campaigning for a ban on chewing tobacco, said surveys conducted in different parts of India had conclusively proved the prevalence of chewing tobacco, especially among adolescents and young adults.

"In a survey of tobacco habits among adolescent boys, we found that 20.8% of boys between the age of 13 and 18 years were using tobacco, both cigarettes and chewing tobacco," Khatri said.

The survey was conducted by the World Lung Foundation, jointly with the World Health Organisation and the US Centres for Disease Control and Prevention, in the northern Indian state of Uttarakhand.

India accounts for nearly a third of all tobacco-related deaths in the world, and the government has been trying to curb tobacco use.

Several health voluntary organisations have mounted a publicity campaign to create awareness about the health risks from chewing tobacco through advertisements on television and radio.

"The ban on chewing tobacco in Delhi is a first step. We will mount a campaign to curb sales of cigarettes as well," said Khatri.

India has banned tobacco advertising for more than a decade. Tobacco companies are resisting a recent order for warning messages to cover 85% of cigarette packages.