Urgent action is needed to tackle the "mountains" of e-waste building up in developing nations, says a UN report.
Huge amounts of old computers and discarded electronic goods are piling up in countries such as China, India and some Africa nations, it said.
India could see a 500% rise in the number of old computers dumped by 2020, found the survey of 11 nations.
Unless dealt with properly the waste could cause environmental damage and threaten public health, it said.