As many as 41 of the 49 samples collected by the Haryana Pollution Control Board from industrial establishments in Gurgaon were found to have exceeded permissible limits. These included several government undertakings, including sewage treatment plants (STPs) maintained by the Gurgaon Municipal Corporation and Haryana Urban Development Authority (HUDA), and the common effluent treatment plant (CETP) of the Haryana State Industrial and Infrastructure Development Corporation (HSIIDC). Officers said checking units in Gurgaon was difficult as industrialists would get wind of raids, or try to get samples changed at the time of testing. To tackle the problem, the pollution control board has devised a strategy. Board chairman Dr A S Chahal told Newsline that he has constituted teams of regional officers (ROs) from Panipat, Sonepat, Faridabad, Bahadurgarh and Dharuhera, and each RO is accompanied by two Sub-Divisional Officers (SDOs) from the Public Health Department and an Sub-Divisional Magistrate (SDM). Besides, a similar team from Gurgaon was also formed, but it was not involved in raids to avoid any collusion. He said the local team was asked to help others locate units in case they have a problem. Chahal made the SDOs and the SDMs rotate different teams.