Registration fees hike by govt can we challenge it in SC

Yes, you can do the same, for this you will have to file a PIL in the High court of your state or you can also file it in the supreme court by following the said procedure:
Procedure to File a Public Interest Litigation
A "Public Interest Litigation", is filed in the same manner, as a writ petition is filed.

In High Court
If a Public Interest Litigation is filed in a High court, then two (2) copies of the petition have to be filed. Also, an advance copy of the petition has to be served on the each respondent, i.e. opposite party, and this proof of service has to be affixed on the petition.

In Supreme Court
If a Public Interest Litigation is filed in the Supreme court, then (4)+(1) (i.e. 5) sets of petition has to be filed opposite party is served, the copy only when notice is issued.

Court Fees
A Court fee of RS. 50, per respondent (i.e. for each number of opposite party, court fees of RS. 50) has to be affixed on the petition.
Procedure
• Proceedings, in the PUBLIC INTEREST LITIGATION commence and carry on in the same manner, as other cases.
• However, in between the proceedings if the judge feels he may appoint a commissioner, to inspect allegations like pollution being caused, trees being cut, sewer problems, etc.
• After filing of replies, by opposite party, and rejoinder by the petitioner, final hearing takes place, and the judge gives his final decision.