Thiruvananthapuram: In a bid to prevent dengue fever spread, the district medical officer has urged the public to observe ‘dry-day’ once-in-a-week at all houses and shops, by eliminating breeding grounds, and follow precautionary measures. Authorities have asked the public to properly dispose of coconut shells, inorganic wastes, plastic utensils, waste tires etc to avoid mosquitoes from laying eggs in stagnant water. Water must be changed at least once a week in the tray behind the fridge and under the flower pot, water coolers, flower vase and the utensils which are used for feeding cattle. Water tanks must be properly covered with nets to avoid mosquitoes entering them. The public must ensure that there is no waterlogging on terrace, sunshade, sunroof etc. The shell used for rubber tapping must be kept overturned, if not in use. Use mosquito repellent creams and wear light-coloured clothes that cover the body fully. Keep windows and doors closed at night and use mosquito nets while sleeping during daytime.