A city-based environment activist has written to the Delhi Development Authority (DDA) alleging “concretisation” of green patches at parks and forests to set up open gyms, which leads to choking of trees. Verhaen Khanna, founder of New Delhi Nature Society (NDNS), said outdoor gyms could be set up without cementing the grass and soil. He said concretisation would affect the groundwater table. “It is not just the ground but even the base of trees is being cemented.This would choke trees. It is also violation of the National Green Tribunal’s order. After the matter was highlighted, concrete at the base of trees was removed but the ground is still being concretised, which would affect water percolation into the soil,” Khanna said. The DDA agreed to cement after locals demanded levelling of the gym surface. DDA officials, however, said their parks are more than one acre in size and concretising a small portion would not affect the water table.“We have been getting a lot of complaints regarding the uneven surface at the open gyms. During monsoon, it gets muddy and people can’t use. Safety concerns were raised. We are concretising or putting synthetic sheets at a small portion where the equipment is installed,” Tarun Kapoor, DDA vice-chairman, said. “I have directed the department to explore other options by which we can made it safe without concretising the surface,” he said. Even as green activists demand de-concretisation of such patches at Sanjay Van and other such parks owned by DDA, many residents said they want the patch to be even, if not concrete, to avoid injuries. “A lot of senior citizens use the open gyms. The uneven surface gets muddy and there are chances of people slipping. L-G Anil Baijal had visited the park last year and people had made the same complaint to him,” said Suresh Goel, a resident of Vasant Vihar and president of the All-India Confederation of RWAs. But other residents want the green patches to be retained. “If a number of patches are cemented within a green space, it will defeat the purpose of having a green lung itself,” said Sudha Sinha, general secretary, federation of co-operative group housing societies, Dwarka. Municipal bodies too have cemented gym surfaces at some parks. “It is important to cement the patch, as mud and slush during rain can damage the equipment and hurt users. In DDA parks, which are bigger in size, cementing a small patch will not affect soil or rainwater percolation,” said Alok Singh, director, horticulture, south corporation. Experts said concretising is not a solution. “Parks serve a crucial purpose as open grounds for water percolation. DDA, residents and other authorities must think of other alternatives,” Kanchi Kohli, researcher, Centre for Policy Research.