Dehradun, July 23 -- The National Green Tribunal's (NGT) principal bench in New Delhi has ordered the state government to file a response to an affidavit detailing 330 allegedly unauthorised structures on the Rispana river's active floodplain in Dehradun, submitted by the National Mission for Clean Ganga (NMCG). The hearing on July 3 concerned a petition by Dehradun resident Niranjan Bagchi. The case concerns unauthorised settlements of the dry bed of the Rispana and the discharge of untreated domestic sewage, dairy waste and industrial effluents into the river. The next hearing was posted to July 28. The bench of justice Arun Kumar Tyagi and expert member Dr A Senthil Vel ordered the state government to submit its response at least three days before the next hearing. According to the NMCG's additional affidavit before the tribunal, 324 of the structures identified in the high-risk "1-in-5-year flood return zone" have been classified as unauthorised. The remaining were categorised as legal but are located within the active floodplain and have been found to be affecting the natural flow of the river and its ecological health. The 1-in-5-year flood return zone refers to an area with a 20% annual probability of experiencing flooding of the severity specified. The affidavit stated that 301 of the 330 structures had existed before October 7, 2016. The six structures classified as legal include government infrastructure. The NMCG on March 24 issued show-cause notices to the Nagar Nigam Dehradun for operating two community toilets, a transformer room and a community hall, the Uttarakhand Jal Sansthan for a water pump house near a community building in Dalanwala, and the Directorate of Primary Education for the Rajkiya Prathmik Vidyalaya on Chander Road. The Jal Sansthan informed the tribunal that its Dalanwala pump house was essential to the city's drinking water network. It said, however, that the process to identify an alternative site and arrange funds to relocate the superstructure while retaining the underground borewell had been initiated. Responses from the Nagar Nigam Dehradun and the primary education department were awaited. The NMCG affidavit stated that it has already directed the state government to remove all 324 unauthorised structures from the active floodplain, install boundary pillars at designated intervals to demarcate the floodplain and take preventive measures to stop future encroachments. The tribunal is also monitoring pollution of the Rispana. The green panel was informed that Uttarakhand Payjal Nigam and Jal Sansthan are working to tap 177 drains discharging pollutants into the river, while the Uttarakhand Pollution Control Board is monitoring the performance of the work. The bench directed the irrigation department, Payjal Nigam, Jal Sansthan and the UKPCB to submit fresh, comprehensive progress reports at least three days before the next hearing.....