India has DDT for household use.
Oh yes I remember DDT even after 63 years after leaving India.
The summer heat occasionally hitting 115F was very effective in killing bed bugs. It was not just the mattresses, the bugs were present in bed frames, bed posts for mosquito netting as well. Everything was laid out on the large open terrace on 3rd floor of house. They soon came scampering out and I was waiting to pick them up and throw them in a cup of kerosene which killed them quickly. Kerosene was used every day in Primus stoves for cooking. Always available in my house.