The Commercial Pilot License (CPL) course regulated by DGCA has a detailed CPL DGCA syllabus that combines both ground/theory and flying training. The CPL exam syllabus DGCA covers subjects like Air Regulations Aviation Meteorology Air Navigation Technical General Technical Specific (if required) and Radio Telephony.
Ground Classes / Theory Portion: To prepare for the CPL exam DGCA you must complete academic hours covering the above subjects. Usually this takes several weeks to a few months depending on the institute and study pace.
Flying Training: This is compulsory. DGCA requires 200 hours of flying experience. Some of this includes solo flights cross country flights night flying instrument flying etc.
Under optimal circumstances many candidates complete the whole CPL syllabus DGCA exam in about 3 to 9 months. This assumes regular uninterrupted training and availability of flying slots.
But realistically due to weather aircraft availability exam scheduling or personal pace this duration can stretch. Institutions mention that one may take up to 36 months to finish all training and clear all subjects.
Another source (AMECET) estimates CPL exam syllabus + training duration typically falls between 12-18 months depending on conditions and schedule.
So in simple terms to go through the cpl syllabus DGCA exam syllabus for CPL subjects and finish CPL exam subjects DGCA expect ground + flying training that usually takes 3-9 months but allow room for up to 36 months depending on your pace and external factors.