The point here is that Tesla can start an assembly plant here .For manufacture of batteries,motors,control electronics etc they need to tie up with local producers whether in India or China.
So your claims like
'India doesn't have big enough infrastructure to manufacture advanced high-end products' doesn't hold water.
We already have the infrastructure to make and transport BEVs,to begin with.We already make.Though this industry wouldn't really take off, unless our government starts to subsidize electric vehicles
REVA - Wikipedia, the free encyclopedia
That said,China is several advantages when compared with India
Lesser bureaucratic hurdles and proper taxation
Cost of production in China is lower
Better transportation infrastructure,including a much less saturated railway system