There is a surge of Culex mosquitoes in Delhi at a time when public health officials are declaring victories against other types of mosquitoes. The situation is complicated because of the changes that have reduced Anopheles. New niches have been found for mosquitoes in urban areas.

Malaria's global footprints have diminished due to interventions such as mosquito nets and insecticides used to target Anopheles. The National Center for Vector Borne Diseases Control in India has helped implement such interventions. In the last few years, the program helped reduce the number of Malaria deaths.

According to a retired government official who worked in northeast India for nearly three decades, the decline in malaria rates in India may be due to the fact that there is more forest in the area. Culex and Aedes, the mosquito genera that transmit the diseases of the tropics, prefer urban and suburban environments. Thousands of people have been killed by the disease in poor countries since 1970.

Scientists are trying to understand how climate change will affect mosquito populations. Climate change has extended the breeding season in Delhi by bringing higher temperatures to months that used to be too warm. The mosquito population has increased due to the untimely rains and the standing water. Areas that used to experience a one-month mosquito season are now experiencing seasons that last six to eight months.

Changes in the environment are what the insects adapt to. Karthikeyan Chandrasegaran is a researcher at Virginia Tech who has expertise in evolutionary ecology and mosquito biology. Public health organizations working in sub-Saharan Africa invested in bed nets for local residents to protect them from the mosquito that bites during the night and day. Within less than a decade, the interventions spiked in effectiveness. The mosquitoes were feeding in the middle of the night after people had left bed. Resistance to commonly used pesticides can be evolved by mosquitoes.

Chandrasegaran said that city-dwellers are likely to be the hardest hit by any problems. Poor waste management is one of the reasons why insects thrive. Some cities, like Delhi, are facing water shortages that have led residents to take scarce supplies in buckets and use them to breed. The conditions are less severe in rural areas where there are more mosquitos.

Rural areas have challenges, too, including limited health care infrastructure. Chandrasegaran said that you would have to tailor your solution to different areas. If you don't identify the pain points, you're going to spend a lot of time and money trying to implement a single scheme across the country, which is going to waste a lot of things.