The top three carcinogens are smoking and chewing tobacco, areca nut (supari) and betel quid (paan, paan masala), which together have made oral cancer the most common cancer in India. Of them, tobacco in its three forms — chewing, smoking and second-hand smoke — accounts for 30% of all cancers in India.

“Most people don’t link viruses with cancer, but viruses such as human papillomavirus (HPV) have been proven to cause cervical cancer and Hepatitis B is linked with liver cancer,” said Dr HaritChaturvedi, director of surgical oncology at Max Healthcare.

Getting vaccinated against both these viruses – Hepatitis B vaccine is a part of routine immunization in India – can protect against cervical cancer in women and liver cancers in both genders, Dr Chaturvedi suggested.

Annually, an estimated 30 lakh people in India suffer from cancer; of these 11 lakh are new cases and the disease claims 5 lakh lives each year. The cancers that claim most lives in India are also the most common, including oral, breast, cervical and lung cancers.

The International Agency for Research on Cancer Monographs lists 481 agents and environmental factors that are carcinogenic, probably carcinogenic, or possibly carcinogenic to humans.

“The international list is massive and some causative agents are not relevant in the Indian context. For India’s monograph, 500 known carcinogens were reviewed and recommendations were given on what is being done and what needs to be done to prevent these cancers,” says a health ministry official who did not want to be named.

India’s National Health Profile 2015 estimates that cancer in men will rise by 19% by 2020, with mouth cancer registering the highest spike. In women, cancer cases will go up by 23%.