Where do you live? Delhi Metro has been quietly expanding rapidly over the past decade, and you can see fairly constant construction and execution. Same with the Gurgaon Metro.
If you are in Bangalore, its metro was a victim of the Siddarmiah-Shivakumar rivalry (Siddaramaiah backed Mysore and Mangalore at the expense of Bangalore to undercut Shivakumar who has significant investments in Bangalore).
> Until land issue is resolved...
This is the biggest timesink for any Indian infrastructure project. Eminent Domain is basically impossible in India under the LARR, which has constantly delayed infra projects across India.