NRIs can buy commercial or real estate properties in India. They may use money in their NRE or NRO savings account or FCNR account to buy property in India. Or they are also allowed to transfer money to India if it is the income earned overseas or their savings abroad. They can remit the money through normal banking channels to India. If their country does not have a Double Taxation Avoidance Agreement with India, the amount will be taxed in both countries.