Can I apply for an India visa on arrival, at the airport?

No, you cannot apply for an India visa at the airport. If you travel for leisure/tourism purposes and are eligible to apply for Indian Visa online, you need to have an issued eVisa before taking a plane to India. Then you can get the visa stamp in the passport on arrival. 

Once again, the India eVisa must be issued in advance of departure, the process takes several days and cannot be done on arrival in India airports.