Condom is a highly regulated product and each condom has to go through stringent quality checking and regulatory approval. Extra Thin or Ultra Thin condoms are just new variants meant to attract more users. That doesn't mean brands can fake and produce some easily-breakable condoms. Even Extra Thin condoms had to fulfill safety parameters set forth by the respective regulatory authority in India.
Every new condom has to go through rigorous testing in approved laboratories before being permitted to hit the market.
Thinner condoms are signs of evolution. Extra thin condoms signify that condom manufacturing is evolving and researchers are able to reduce the thickness of the condom without compromising on its strength to prevent bodily fluids from mixing.
So, thinner condoms are as safe as other condoms. Brands that don't have extra thin condoms may eventually roll out their thinner condoms in the near future. When more people begin to prefer 'thinner' variants, every brand will be forced to introduce thinner variants to stay relevant to market demand.