A couple of years back, India made a big change to its visa policies for tourists for additional security measures. There was some abuse found of the tourist visa, with unscrupulous visitors making multiple trips. Policy was changed to not allow tourist visa holders back into the country within 2 months of making their last visit.
Unfortunately, the policy did lead to a drop in tourist traffic to India, and now there is a rollback. Last week, India changed the policy to allow visitors to the country to travel on the same multiple entry tourist visa multiple times without a 2-month gap between their visits. Which means, if you wanted to make a landing in India and go around the neighbouring countries with your base here, you could do that once again.
And yes, there is always that visa on arrival for some countries.