At Sea, Bay of Bengal

Here we are, some place half-way from Thailand to India, where I will be spending the next couple of weeks, along with stops in Sri Lanka.
 
Years ago in India they decided to change from two time zones to just one (even though the country is quite broad). I’ll go along with that.

Additionally, they decided to change the time by 30 minutes. So tonight we set our clocks back ½ hour. What’s up with that?