The first thing to keep in mind is that you can get anything in India.
Basically, in Indian cities, you can buy what you need for your trip. Therefore, it will be more enjoyable to travel with light luggage, with the feeling of procuring locally rather than worrying about coming from Japan with large luggage.
It's fun to make custom-made Indian folk costumes as well as T-shirts and pants. You can also get the fabric cheaply.
When using Japanese electrical products, the voltage in India is 220-240V, 50Hz, so you have to pass through a transformer, but you can purchase the transformer and plug in India. You can use your computer as it is, but it is safer to use a stabilizer (voltage ballast) because the voltage in India is not stable.
Contact lenses and glasses can also be made in India. There are also branded frames for eyeglasses, and the lenses are cheap, so I recommend it to anyone who wants to make them.
The currency used is Ruby (Rs) Paisa (P). Banknotes are 5, 10, 20, 50, 100, 500, 1000 rupees. The coins are 1, 2 and 5 Paisa.Credit cards can also be used at many stores such as restaurants and department stores in urban areas, so it is convenient to have one.
Anyway, my heart is light and my luggage is light!