Rubbish collectors could be seen wading through mounds of garbage at a dump in Kathmandu, Nepal, late last month.
Infrastructure problems in the country such as the failure to clear rubbish promptly make areas such as these havens for mosquitoes to breed.
Dengue fever surfaced in the country just 14 years ago, but has since been reported across Nepal as dengue-spreading mosquitoes gain a foothold in a nation that is getting warmer due to climate change.
The situation is at its worst during the monsoon season, when water collects in rubbish dumps and turns them into hotbeds of mosquito breeding. TOMORROW: Look out for the fifth of six weekly special reports in The Sunday Times examining how global warming is affecting the world.