You mean for agriculture? Because using DDT for disease vector control was never internationally banned (only banned at the national level).
It's banned in agriculture because it kills stuff other than the mosquitoes. In particular, its use is restricted by the "Stockholm Convention on Persistent Organic Pollutants". Persistent Organic Pollutants are pretty much as bad as they sound, and DDT is one.
It was used in Africa, at least in 2016.
http://chm.pops.int/Implementation/DDT/DDTMeetings/DDTEG6201...
> Why don’t we use DDT today?
You mean for agriculture? Because using DDT for disease vector control was never internationally banned (only banned at the national level).
It's banned in agriculture because it kills stuff other than the mosquitoes. In particular, its use is restricted by the "Stockholm Convention on Persistent Organic Pollutants". Persistent Organic Pollutants are pretty much as bad as they sound, and DDT is one.