As researchers working on the sustainable management of urban waste, we are deeply concerned about developing countries' escalating production of municipal solid waste and of construction and demolition debris. Dump-site landslides have killed at least 220 people over the past 18 months in Shenzhen, China, in Addis Ababa, Ethiopia, and in Colombo, Sri Lanka. This growing threat to people and the environment demands greater attention, broader oversight and proper management.

Developing countries such as China and India are urbanizing at an unprecedented rate (see X. Bai et al. Nature 509, 158–160; 2014). Many of the poorest cities in Africa and Asia are likely to double the waste they generate within 20 years. Drastic action is needed to control this trend (see, for example, D. Hoornweg et al. Nature 502, 615–617; 2013).

Most such urban waste ends up in poorly operated landfill sites, or is dumped or burned. Some 3 billion people worldwide are not served by controlled disposal facilities. It is therefore crucial for governments in developing countries to provide safer alternatives for waste disposal, to pass and enforce regulations to eliminate the open dumping and burning of waste, and to finance sanitary landfill and recycling programmes. As cities continue to expand, careful and sustainable planning is essential.