The telecoms regulator in India has put a cap on the number of text messages which can be sent from a mobile phone.
Under the new rules, no-one will be able to send more than 100 texts in a day, officials say.
The ruling is expected to be a big relief for millions of mobile phone users who have to deal with dozens of unsolicited text messages every day.
India has made several attempts in the past to rein in tele-marketing firms who bombard mobile phone users.
A BBC correspondent in Delhi says all the earlier attempts to deal with unwanted commercial messages and calls have been unsuccessful.
Subscribers can currently register their numbers with a "national do not call" list by sending a message to 1909.
In December, India announced plans to impose heavier fines on tele-marketing firms who called or sent text messages to those registered on a "national do not call" list.
The Telecom Regulatory Authority of India (Trai) also barred commercial calls or messages between 9pm and 9am.
But the messages continue to be received late at night, sometimes even at 3am, our correspondent adds.
Many people have complained that they feel harassed by calls and text messages from tele-marketers trying to sell everything from credit cards to real estate to "slim sauna belts for weight loss".
Trai officials say the number of unsolicited commercial calls have come down drastically since the "do not call" registry was launched in 2007, but the number of text messages went up exponentially.
The daily cap of 100 messages per phone is expected to deal with the problem, they say.
India has the fastest growing mobile phone market in the world, with more than 700 million subscribers.