Indian space program is one of the most reliable (less number of accidents) space programs in the world.
Just yesterday Indian successfully launched PSLV to put 5 foreign satellites in orbit. It's 26th consecutive successful flight.
It is the most reliable and cost effective rocket in the world right now.
Salaries do play a part in bringing the cost down but that is not the only reason. ISRO functions like a very agile organisation with small teams focusing on specific targets with autonomy. Also, a lot of cost is saved in the testing phase as well.