I was introduced to Feluda quite early, when my mother brought it from the school library. At that time I had no idea that Feluda was one of our very own, partly because I had no knowledge of who the great Satyajit Ray was. Later I managed to dig deep in the matter, if you call searching Wikipedia digging deep, and then realised the scarcity of fictitious home produced detectives in India. The best thing about Feluda is that you don't realise how ridiculously simple it is, in content and in language. But the story, in whole, strikes the heart deeply. Of course, then there  is Tapesh, who serves as the Watson to Feluda, whose full name, by the way, is Pradosh Chandra Mitter, and narrates the story in a charming yet simple manner. Without that type of narration I do not think Feluda could have reached the heights he has, atleast in Bengal. But one of the best characters is Lalmohan Ganguli, whose innocent humour is deliciously meaningless in the context of the plot, but still leaves us smiling everytime we read it. The most amazing is that Satyajit Ray took time from his busy schedule to write such novels, which while refraining from touching upon stuff such as gore and other such things, and yet manages to engage us till the last word.
One other detective I have found that India has truly created, is Byomkesh Bakshi. I have managed to read only one book of the Bakshi series, but I had the pleasure to watch all the episodes that Doordarshan produced, I think, two or three decades ago. It starred Rajit Kapur as Bakshi, the great Satyanweshi (seeker of truth) and K.K.Raina as his loyal friend Ajit Bandyopadhyay. The series was excellent. Some people might call it too simple, but that's what, according to me, added to its charm.