As Section 29 of the Code of Criminal Procedure, 1973, Magistrate of 1st Class:
Can pass sentence for term up to 3 years imprisonment or
Fine up to ` 10,000 or
Both
As per Section 30 of the Code of Criminal Procedure, 1973, the Court of a Magistrate may award additional imprisonment in default of payment of fine. However the term of imprisonment shall not exceed 1/4th of the term of imprisonment which the Magistrate is competent to inflict as punishment for the offence.
In present case, the Judicial Magistrate of the First Class can inflict sentence of imprisonment which may extend to 3 years as punishment for the offence of theft. Therefore, the term of additional imprisonment which can be awarded in default of payment of fine cannot be more than 1/4th of 3 years. In other words, the term of additional imprisonment in default of payment fine cannot exceed 9 months. [36 months × 1/4 = 9 months]
The accused is advised to challenge the validity of the sentence accordingly.