Facebook's Internet.org has opened its free Internet access platform to any low-bandwidth online service that meets its technical guidelines for running on basic phones.
Internet.org's goal is to provide underprivileged people in Asia, Africa and Latin America with access to select online services without mobile data charges.
However, it ran into trouble in India where it was criticized by local net neutrality activists for creating "walled gardens" that provide free access only to a few preferred content providers and services, including Facebook.
Under pressure from the activists, some of the 38 websites and services that had joined Internet.org and operator Reliance Communications for the project opted out of the alliance or signaled that they were ready to leave. These included the Times Group, which withdrew some of its media sites, and travel site Cleartrip.
On Monday, Internet.org said it had decided to give people more choice over the services they use and would welcome to its platform websites that were simple and data efficient. Websites will not pay to be included, and operators won't charge developers for the data people use for their services.
Operators also do not get paid to offer the free access, said Facebook CEO Mark Zuckerberg in a video posted to the Internet.org website. He added that the program would support itself as users of free basic services will move to paid services to access the broader Internet, making it worthwhile for operators to offer the free services.
In a response to his critics in India, Zuckerberg said net neutrality should not prevent the underprivileged from accessing the Internet, which can provide them a way out of their poverty, "It is not an equal Internet if the majority of people can't participate," he added.
"We're building an open platform and anyone who meets these guidelines will be able to participate," the Internet.org project, launched in 2013 by Facebook and other tech companies, wrote in a post on its website.
The websites will have to be optimized for browsing on both feature and smartphones and with limited bandwidth. Services should not also use voice-over-Internet Protocol, video, file transfer, high resolution photos, or a high volume of photos.
Net neutrality has emerged as a controversial issue in India after the Telecom Regulatory Authority of India asked in March for comments on a framework for Internet applications and services that ride on mobile operators' networks.
One mobile operator, Bharti Airtel, introduced a platform, called Airtel Zero, so that app developers could offer so-called zero-rating apps to customers after paying the operator a fee. That move was also criticized by pro-neutrality groups who worry that operators are looking to charge providers of websites and mobile apps to deliver services to their customers.