Indian OTA Cleartrip has pulled out of internet.org, the Facebook-run initiative designed to make internet access more widely available around the world.
Net neutrality campaigners in India have argued that internet.org threatens online freedoms because, while it is free for anyone with a connection, the sites which can be accessed are limited. The app, through which the prescribed sites are accessed, is also only available via the Reliance network, one of India's biggest telecoms providers.
There are also concerns that internet.org - and similar services - is a Trojan horse with the ultimate aim of securing access to highest-speed connectivity across what could be a regulated multi-speed internet infrastructure.
Facebook founder Mark Zuckerburg set up internet.org in 2013 and it is available to more than 600 million people in Zambia, Tanzania, Kenya, Columbia, Guatemala, Ghana , the Philippines and most recently India.
The service launched in India this February with 40 partners, including Cleartrip.
However, this week Cleartrip announced that it was pulling out of the project.
It said that "since there was absolutely zero money changing hands, we genuinely believed we were contributing to a social cause."
Upon reflection however, Cleartrip became uncomfortable with "the idea of large corporations getting involved with picking and choosing who gets access to what and how fast." It decided that its involvement with internet.org was incompatible with its backing of net neutrality and withdrew as a result.
Cleartrip made the announcement 24 hours after Flipkart - one of India's biggest online retailers - pulled out of Airtel Zero, a similar "free" internet access service run by Airtel.
And following Cleartrip's withdrawal from internet.org, other launch partners threatened to pull out. The Times Group of India led the call, but only promised to withdraw certain sites - its Times of India news site will only be removed if and when other news and content providers - ie its competitors - do so as well.
Internet.org founder and Facebook CEO Mark Zuckerberg took little time to respond, writing to the Hindustan Times, "strongly disagreeing" that "offering some services for free goes against the spirit of net neutrality".
He explained:
"To give more people access to the internet, it is useful to offer some services for free. If you can't afford to pay for connectivity, it is always better to have some access and voice than none at all."