"This indicated Apple's willingness to allow more extensive monitoring of its supply chain," said Ma.

Apple shares suppliers with other brands and should not take sole environmental responsibility, but it has been active in solving pollution problems, he added.

Today, Ma describes his cooperation with Apple as "close and deep" -- they work together when problems arise.

"Sometimes we work with third parties like Ma Jun at the IPE," said Jackson. "If we have a violation, sometimes we will actually bring Ma Jun into the facility or his organization in, to make sure that it is completely audited together."

Ma's team has established a pollution databank based on statistics released or reported by governments and the media since 2006.

Apple uses the databank when auditing its suppliers or choosing new ones.

"Apple Opens Up", an IT industry supply chain investigative report released in January 2013 by five Chinese NGOs including IPE, said that among 29 brands they had been following, "the biggest transformation has been seen in Apple".

The report concluded that Apple has increased transparency and started green purchasing that forced suppliers to improve their environmental performance.

"Apple as a role model has successfully influenced other brands to make changes too," said Ma.

Another area Ma believes Apple has taken a lead on is its increased control over not only its suppliers but raw material suppliers, as pollution from the IT industry comes mostly from the origin.

"Our belief is that as long as we understand the whole picture of where the product comes from, we can work to reduce our (carbon) footprint to make our environmental impact smaller," said Jackson.

Ma said that Apple has done "significant" work in this area, adding that an evaluation document his organization is working on will show Apple ranks number one among all other brands. The final ranking is expected to be released at the Eco-Forum Global to be held in southwest China's Guiyang City in July.

For a company like Apple, which has sold more than one billion iPhones, iPads, Macs and iPods worldwide over the past seven years, any small but green measure will have a positive impact.