In the United States.
Donor agencies such as the U.S. Agency for International Development have pressured Belize, Bolivia and Mozambique not to use DDT — or risk losing their aid money, adds Bate.
This is partially true, and partially wrong. Most of the pressure was aimed at stopping aerial spraying campaigns, and one of the main reasons to do that was to reduce the occurrence of resistance. However, malaria funding has focused on medicines for active malaria cases and not as much on prevention efforts, and they aren't funding DDT programs for indoor and wall spraying, which is effective. This may be due to environmental concerns in the U.S. -- it's clearly a factor for European aid agencies. I agree with the position that the aid programs should include funding for indoor spraying campaigns. So, apparently, does the World Health Organization:
"Most of the pressure was aimed at stopping aerial spraying campaigns"
Un-necessary and un-warranted pressure.
The letter you cited claimed:
"DDT is not used for outdoor mosquito control, partly because scientific studies have demonstrated toxicity to wildlife,"
... yet many of the claims from eco-extremists on DDTs effects have been punctured. This includes the phony "Silent Spring" claims.
They support stockholm convention that says nobody should be producing or using DDT except those that notify the Secrtariat of their use, and they cant use it all all except through WHO guidelines, and they cant use it when 'safe' alternatives exist.
The Convention is all about eliminating DDT use, no question. It's a VERY restrictive global regulation.
WHO is merely saying that they can continue using DDT indoors for the time being.
As for recommending indoor use only for DDT, last I checked, mosquitos natural habitat was outdoors, and the best defense is a good offense.