Dear leaner,

Yes you can do at regular for diploma in sanitary inspector also you can get it from distance as it's duration is 1 year and eligibility is 12 th and any graduate from any stream can take it .

Where as ba political science it is a graduation course which is 3 years of education in particular subject.some colleges provide it online .

Piece of advice , you cannot place leg  in two boats at same time, therefore you'll fall. It's ok if you take both as serious ,but every graduation college ask you certificates before getting admission. If you spare your certificate already in diploma you can't maybe so careful while taking admission.

All the best.