Knowing Hindi, I can see the Indian accent following the pronunciation allowed by the sounds of the Hindi alphabet.
The fact is, there is no single Indian accent- the accents change from north to south, east to west, and all tend to reflect the language used in the region concerned.
For example, it's hard to get the 'Ae' sound in the word 'apple' using the Devanagiri script.
Interestingly, it's easier to compose English words in Hindi with American accent-like sounds, than it is, with the British accent, for many words.
Our accents are far closer to those of Wales than to UK.
Look, Wales was a desperately poor country during the glory days of the Raj. Welshmen found themselves faced with working in the mines, milking cows or going to India.
They went to India.