Hi
I am intersed in online ph.d. In economics .can this phd recogised by ugc

Who's UGC ?

You would need to ask them if they would accept such a qualification, many companies don't especially at the higher end, like PhD.

There are many online phd offer available.
But it has no value under UGC guidelines.
UGC has ban even the distance mode phd in India.
If you like to do Phd has you want career prospective then u need to do in regular mode.