Yes, Iranians can hold dual nationality. However, the government of Iran would recognize ONLY the Iranian nationality of its dissidents.
India does not allow dual citizenship.
Yes, Thailand allows dual citizenship.
Dual citizenship has been allowed in Brazil since 1994.
No, it's South Korea that does not allow dual citizenship.
Yes, it does.
Israel allows dual citizenship for those who immigrate to Israel based on Law of Return (aliyah): you have to be Jewish to qualify to hold dual citizenship in Israel.
Liberia
Yes, both countries allow dual citizenship. However, if you live more than ten years outside Ireland, you will lose your Irish citizenship.
Yes, there is. Both countries allow dual nationality.
The rules of dual citizenship are quite easy to understand. Most countries neither deny or recognizes dual citizenship. However, if you are a dual citizen you must enter the country with the country's passport you own.
Yes, in the United Kingdom, dual citizenship is legal. The current law, the Nationality Act of 1948, does not disallow it.
India does not allow dual citizenship. But you can apply and get a passport-like booklet, at the nearest embassy and consulate general, that will allow you to travel to India visa-free.