Can we wish non-Muslims "happy holi", "happy Diwali", etc.?

I am working in MNC software company. Over here all employees, mostly non-Muslims, wish each other with *"Good morning"* and *"Good night"*. And during special festival with *"Happy Holi"*, *"Happy Diwali"* etc. So, is this allowed in Islam? Can we wish them during ordinary days and during festivals? Are there any alternatives to wishing them with *"Good morning"* and *"Good night"*? **EDIT** Thanks Everyone, i got answer for secular greetings (good morning), that we can wish them, But can we wish religious greetings (happy diwali , happy holi,...) ? ---------- **Final EDIT** Thanks everyone.. I Got answers of my questions. Yes, We can greet non-muslims with Good Morning or Good Night. But, **We can not wish non-muslims to on their Religious Festival.** Reference: Fatawa Mahmoodiya 19/567, Kitabul Fatawa 1/304 http://masaail.com/diwali-aur-un-ke-naye-saal-ki-mubarakbadi-dena/