You’re supposed to declare Indian rupees in excess of ₹10,000, any amount of cash over US$5000, or a total amount of currency over US$10,000 on arrival.
You’re also prohibited from importing more than one laptop, more than 2L of alcohol, more than 100 cigarettes or equivalent, or gifts and souvenirs worth over ₹8000.
Note: Also the restrictions on exporting antiques.
FYI: To protect India’s cultural heritage, the export of certain antiques is prohibited – especially the export of those that are verifiably more than 100 years old. Reputable antique dealers know the laws and can make arrangements for an export-clearance certificate for old items that are OK to export. Detailed information on prohibited items can be found on the Archaeological Survey of India (ASI) website (http://asi.nic.in).
The Indian Wildlife Protection Act bans any form of wildlife trade. Don’t buy any product that endangers threatened species and habitats – doing so can result in heavy fines and even imprisonment. Banned items include ivory; shahtoosh shawls, which are made from the down of chirus (rare Tibetan antelopes); and anything made from the fur, skin, horns or shell of any endangered species. Products made from certain rare plants are also banned.