Suffering in abject poverty is infinitely worse than pollution. It doens't even compare. Thus, developing countries should optimize for economic efficiency. Hurting human well-being in favor of environmental "well-being" is criminal.
http://www.who.int/mediacentre/factsheets/fs292/en/
Over 4 million people die prematurely from illness attributable to the household
air pollution from cooking with solid fuels.
More than 50% of premature deaths among children under 5 are due to pneumonia
caused by particulate matter (soot) inhaled from household air pollution.Pollution really is way, way down on the list of concerns for people in impoverished nations. Water, Shelter, Food are much more pressing concerns.