There is no limit on sending money from USA to India, provided you pay the required taxes. But, there is a limit of US $14,000 per person per year for gift tax free transactions. Any amount sent above US $14,000 per person per year, the sender is responsible for paying the gift taxes. Note that there is no income tax deduction for the amount you send.
Disclaimer: The information presented here is for general information purposes only and does not constitute tax advice. Please consult your CA, CPA, tax-expert or tax attorney for specific tax advice and inquiries. Visit IRS Website for US tax information. Visit RBI Website for Reserve Bank of India and Income Tax Department Website for Indian regulations.