Reptilians love to use nuclear techonologies as their weapons and energy.
Some information says Reptilians have blood based on copper (Humans have blood based on iron). Their copper based blood can eliminate radiation contaminants faster than iron based human blood.
They prefer living in radiation contaminated environment because their home planets are all contaminated by radiation.
The description above can match the condition in Hiroshima & Nagasaki.
Hiroshima Dome is still standing. One of my friends visited and stayed inside the Dome. She told me she felt really ill while she was under the Dome. She thought spirits of killed people made her sick. But actually, the remaining radiation made her sick.
Just like Mohenjo Daro, some radiation can remain for tens of thousands years.