Eradication of mosquitoes was a very popular cause in the 20th century, but the means by which that was being done caused a lot of incidental environmental dama

Eradication of mosquitoes was a very popular cause in the 20th century, but the means by which that was being done caused a lot of incidental environmental damage (draining wetlands, thinning bird shells, gassing other bugs, etc) so the brakes were pulled. Since then new techniques have been developed but they need to overcome the caution people now have for the whole idea.