Original sentence: After an extensive anti-mosquito program with DDT, there were only 17 cases reported in 1963.But after DDT was banned, malaria rebounded to 600,000 cases in 1968 and the first quarter of 1969.In Ceylon/Sri Lanka, in 1934-55, there were 1.5 million cases of malaria resulting in 80,000 deaths.It was banned for use in many other countries in the 1970s due to its alleged negative environmental impact.Paul Hermann Müller was awarded the Nobel Prize in Physiology or Medicine 1948 “for his discovery of the high efficiency of DDT as a contact poison against several arthropods”
Edited sentence: It was banned for use in many countries in the 1970s due to its negative environmental impact