It used to be the largest builder in North India, but they were very close to Akilesh Yadav and the Samajwadi Party.
After BJP won the Uttar Pradesh state elections in 2017, Jaypee (which was already struggling with finances) lost a number of tenders in NOIDA, loans were called, and they along with other similar builders caused IL&FS to become insolvent.
It's very similar to the Ghost Cities you'd see in China in the 2000s
Also, India has Google Street View. Go explore OMAXE New Chandigarh, Sector 128, Kharar, etc.
Lots of half built buildings in middle India.
And this is why PMAY-U is being pushed so hard by all parties in India - it's an easy way to bail out builders without breaking financial laws.