Apple had decided against allowing the iPhone to be rated in a new environmental ranking scheme that has been developed by the UK carrier O2. The scheme has been brought to reality with the aid of sustainability advisory group called the Forum For the Future.

Accordingly, phones are rated based on the environmental impact caused by factors such as manufacturing, energy efficiency, packaging and recyclability. The score is from zero to five and is determined on 63 questions that are given to the manufacturers.

Most of the major phone manufacturers such as Nokia, Samsung and Sony Ericsson have signed up for the scheme. According t to O2, 93% of all devices should be covered by the scheme. Research in Motion (RIM), the maker of the Blackberry, has promised to enroll in the scheme next year. All this makes the iPhone’s absence very interesting.

Apple itself decline to comment on its decision but it did highlight its own environmental reports on the iPhone, which suggest that the iPhone has a minimal carbon footprint. However, critics charge that if Apple’s evaluation process lacks transparency.  Apple continues to promote the iPhone as a product with a low-carbon footprint despite its refusal to join the scheme run by O2.