As per the regulations governing the import of drugs for personal use as part of a passenger's bonafide baggage in India, the maximum limit for importing a single drug is generally up to 100 dosage units (e.g., tablets, capsules) or a quantity that does not exceed 30 days' supply, whichever is less. This is subject to certain conditions, including the passenger declaring the drugs to customs and providing a valid prescription from a registered medical practitioner. The exact rules can be subject to updates and specific circumstances, but 100 dosage units is a commonly cited limit for single drugs.