The criticism of the initiative comes from the fact that the reductions in emissions, which is the subject of the protocol, even if achieved, would not bring any substantial results. Some countries since withdrew from the treaty (Canada, Russia, Japan, and New Zealand), whereas some did not ratify it (the US). Developing countries were advised to comply voluntary, meaning that the reduction scheme is not binding for them.
China and India are the two largest developing countries which are not obliged to comply with the protocol. Together with the US, Russia, and Japan, these are the five top CO2 emitters globally, none of which is committed to CO2 targets, at the moment. The major polluters are the ones that are not bound by the CO2 reduction targets.