Hi aspirant

Every state conduct counselling on the basis of participating institutes and seats availability.

For admission in any course across the country ,different counselling is organised as per the needs.

For exa: JOSSA counselling for admission into IITs/NITs/IIITs/GFTIs ,AIQ counselling for MBBS admission,State counselling for Engineering and medical and other counses.

Open counselling is considered as spot round counselling or it can be said as last phase of counselling.

When seats of different colleges are not filled in subsequent counsellings,OPEN counselling is conducted .Different states/bodies may have certain rules and regulations for the counselling procedure which you can know through the official website of counselling conducting body.

Almost each state conduct but as per the needs.

Hope this was helpful.