A Muslim giving a talk on a radio station, first greets with the Hindu greeting of 'namaste', then with the Islamic Salaam, then with other greetings.

Answer

It is haraam to greet with the Hindu greeting of 'namaste'. While other forms of kuffaar secular greetings are also prohibited, the Hindu religious form of greeting is worse. It is kufr. The fact that he gave it preference over 'Assalaamu Alaikum', mentioning the latter after the Hindu greeting, renders him a kaafir.