Thus international organizations such as the IMF regard carbon pricing measures - either through taxes or trading systems designed to behave like taxes - as "potentially the most effective mitigation instruments" (Farid et al., A strategic approach can help to ensure that policymakers maximize the potential of the environmental taxes they introduce to meet the environmental, economic/fiscal or social policy priorities and objectives they have defined. This may include specific measures which are politically feasible and where windows of opportunity for reform exist, or a comprehensive process of environmental fiscal reform. Subsidy reform can free up substantial revenue to fund development objectives, including sustainable development goals. Careful planning of the process - including careful sequencing, accompanying social and economic policies, and measures to counteract price rises - and strategies to build support for reform at all levels of society are essential to prevent policy reversals.