Mumbai,  -- Anti-smoking activists have another reason to demand a smoke-free city. Medical experts claim that the rising number of smokers is abetting the spread of tuberculosis (TB), a disease that claims over three lakh lives in the country each year, as cigarette smoke lowers the body's immunity. Medical practitioners say the fight against the killer disease has become much harder due to rising pollution levels and the large number of smokers in the city. "At least 70 per cent of Mumbai is infected by the Mycobacterium Tuberculosis (the causative organism of tuberculosis). It is when their immunity drops that they contract the disease. Smoking and air pollution reduce the immunity of the respiratory system, making it easier for the disease to manifest and spread," said Dr Ashok Mahashur, chest physician at Hinduja Hospital. Dr R.S. Birla, a physician at Tata Memorial Hospital, said passive smokers were worse off than smokers. "A passive smoker is 100 times worse hit by the effect of the smoke. This makes them far more vulnerable to infection. So even if a person is a non-smoker, having friends who smoke can increase the risk of their developing tuberculosis," he said. Doctors claim that apart from weakening a person's resistance to the disease, smoke and pollutants also lower the body's response to the drugs used to treat the disease, making treatment longer and far more expensive.

"Good hygiene and awareness are necessary to fight this disease, but we won't get anywhere if we continue to live in an environment in which the organism thrives," he added.