Hello Sourav,

Some of the best Institute for distance learning are-

• Institute of Management Technology, Ghaziabad- IMT is considered as one of the top business schools in India. It offers distance learning course. The 2 year MBA and Distance education/learning offered by the institute is considered best in Delhi and NCR.
• Narsee Monjee Institute of Management Studies -NMIS is one of the top ranked management institute in Mharashtra as well as India. NMIMS offers the 2 years PG diploma course is different streams under distance education system.
• Symbiosis centre for distance learning -It is also one of the best institute in India for distance learning. Institute's 2 year PGDM(MBA) is one of the most popular management program in India. You have the advantage of choosing it from various streams ranging from HR Management to finance to marketing.
• Indira Gandhi National Open university - The most common name that comes when we think of distance learning is IGNOU.IGNOU is world’s largest university in  terms of the students that have taken admission.

There are many more Institutes out there.

I hope it helps

Thank you