Dehradun: Stagnant water in drains across several residential colonies in Dehradun following recent rain has raised concerns over mosquito breeding and a possible rise in dengue cases ahead of the monsoon.Residents from areas including Sahastradhara Road, Canal Road and Chakrata Road said water accumulation in drains, open spaces and around construction sites could lead to an increase in dengue cases if preventive measures are not intensified soon.Parul Sharma, a resident of Ekta Vihar on Sahastradhara Road, said water had accumulated at several spots after the rain. “Stagnant water acts as a breeding ground for mosquitoes. Construction sites along Sahastradhara Road also have water accumulation and, if the water cannot be drained, chemical larvicides should be sprayed,” she said.Sharma said dengue was not as common in the city decades ago and stressed the need for long-term civic measures. “There used to be hardly any dengue cases in the city in the 1990s. Fogging alone will not solve the problem. The drainage and sanitation system needs fixing,” she said.More than 490 dengue cases were reported till Sept last year, with infections being reported from April and peaking in July.Residents also highlighted the need for greater public awareness to prevent mosquito breeding. Swarnali Ray, a resident of Yamuna Colony on Chakrata Road, said people often unknowingly contribute to water accumulation near their homes. “We need more awareness on how easily we contribute to the problem by leaving junk in our backyard and allowing water to collect in it,” she said.Ray, who contracted dengue two years ago, said awareness drives should begin earlier and reach residential colonies directly. “More awareness drives are needed in residential colonies, not just in schools, and they should have started by now,” she said.In Surbhi Enclave on Canal Road, resident Yesh Veer Arya said the roads were not fixed after power lines were laid underground and the work has added to the mess. “Fogging was done for the first time in the area only on Saturday,” he said.Chief medical officer (CMO) Dr Manoj Sharma said the health department carries out preventive and containment measures every year before and during the dengue season. “Rapid response teams are formed annually to tackle cases and carry out containment activities in affected areas. Larvae identification activities will begin from June 1,” he said.According to the CMO, routine fogging is carried out by the municipal corporation in areas under its jurisdiction, while the health department gets fogging done through the civic body in places where dengue cases or mosquito larvae are found.Six dengue cases have been reported in May so far, three of them from Dehradun district. “We have initiated surveillance and containment activities in the areas where the three cases were reported and informed the respective districts about the remaining three cases,” Sharma said.Last week, the state health department directed all districts to intensify dengue preparedness amid concerns over a possible rise in cases during the monsoon. Director general (health) Dr Sunita Tamta instructed officials to identify waterlogging spots, carry out fogging and larvicide spraying drives, launch fever surveillance campaigns and ensure adequate preparedness in hospitals, including isolation wards, medical supplies and platelets.