Question

how are political parties recognised as regional and national parties in India​

Answer 1

National parties
A registered party is recognised as a national party only if it fulfils any one of the following three conditions: A party wins 2% of seats in the Lok sabha from at least three different states. ... A party gets recognition as a state party in four states.

A Regional Party is a party that is present in only some States. Conditions required for a party to be recognized as a regional political party are: (a) A party that secures at least six percent of the total votes in an election to the Legislative Assembly of a state.