Kolkata, Dec 01 (ANI): Sex workers in Sonagachi, one of Asia's largest red light districts located in Kolkata, pledged not to have sex without condoms to mark the World AIDS Day on Monday. The Human Immunodeficiency Virus (HIV) that causes Acquired Immune Deficiency Syndrome (AIDS) is spread via blood, semen and breast milk. There is no cure for the infection, but AIDS can be kept at bay for many years with antiretroviral drugs. In the global battle against HIV/AIDS, sex workers like those in Sonagachi are a crucial link in a chain of infection. A 19-year-old sex worker who is in this profession because of her truant husband, said that cleanliness is very important to fight HIV/AIDS. The Project Director of HIV Intervention Programme in Sonagachi, Puja Roy, said that free condom service was initiated aiming to make Sonagachi a 'zero AIDS' region.