At least five persons were hospitalised on Thursday after chlorine gas leaked from a waterworks at Sector 20 in Panchkula. Over 30 persons complained of giddiness and uneasiness after the gas was leaked. The residents of near-by houses were moved as they complained of itching in their eyes and other effects of the gas. Mayor Upinder Ahluwalia, who visited the site, said the chowkidar of the waterworks was most affected. The waterworks, she said, is of the HUDA and its officials were at the site taking stock of the situation.