'My grandmother sits on the road' would be मेरी दादी सड़क पर बैठती हैं।
मेरी दादी सड़क पर बैठ रही हैं is 'My grandmother is sitting down on the road' as in she is in the process of sitting down
मेरी दादी सड़क पर बैठी हैं is 'My grandmother is sitting on the road' as in she is seated
There is at least one instance when this expression looks valid:
In our case, maybe someone wanted to get rid of grandma or use her as a decoy !!-( Unfortunately, some elderly people would do that on their own...
Not saying this is impossible in every English dialect. (I assume it's possible in Indian English for the obvious reasons!) But when I came upon this sentence "in the road," which is what I assumed the sentence meant (disturbing though the situation be) wasn't accepted, so I wanted to verify what this sentence meant.
That article doesn't seem the best of references given that newsner appears to be a less-than-journalisticaly-credible Swedish site, and it also includes the unusual word "softwares," which Wiktionary lists as "Generally an error by non-native speakers." The source article it links to uses the expected "in the road."