Genetic engineering has failed to increase the yield of any food crop but has vastly increased the use of chemicals and the growth of “superweeds,” according to a report by 20 Indian, southeast Asian, African and Latin American food and conservation groups representing millions of people.

Global warming could be slowed down if governments cleaned up what's known as black carbon from industry and cooking fires, 50 of the world's leading atmospheric scientists said on June 14.

Major air pollutants like black carbon, methane and ground level ozone mostly result from the soot and gases formed by the incomplete burning of fossil fuels, wood and biomass.