Global Warming as we all know is one of the serious environmental issues resulting from Green House Effect. Out of all Green House Gases (GHGs), carbon dioxide is the most significant one as its concentration in the atmosphere is increasing at an alarming rate. The most interesting aspect of the GHGs is that they allow the incoming solar radiations to come to earth, but do not allow the longer wavelength radiations of the earth to go up. These are reflected back to the earth surface. As a result the earth's surface temperature is getting warmer. This progressive warming up of the earth's surface temperature due to the blanketing effect of heat trapping green house gases is known as Green House Effect or Global Warming. Global warming is a potential threat to both our physical and biological environment. A slight increase in global surface temperature can seriously affect world's food production and could lead to rise in sea level, change in rainfall and climatic pattern across the world. Having realized the deadly effects of global warming, the international community has been debating on policies and measures to be adopted globally for quite some time now. One of the first initiatives in this direction was the Earth Summit held at Rio de Janeiro in 1992, where most of the nations of the world agreed to combat climate change. Subsequently, under the aegis of United Nations, United Nations Framework Convention on Climate Change (UNFCCC) came into force. This convention set the objective of stabilizing atmospheric GHGs at a safe level based on the Kyoto Protocol. Although UNFCCC adopted Kyoto Protocol in December 1997, it has finally come into force from February 16th 2005. The Kyoto Protocol is a legally binding agreement to tackle climate change through reduction of green house gas emissions. The protocol established three innovative mechanisms viz. Joint implementation, International emissions trading and Clean Development Mechanism (CDM). The CDM is one of the mechanisms of Kyoto Protocol, which allows developing countries to achieve sustainable development and at the same time assists developed countries (Annex-I countries) in meeting their emission targets. What is CDM? Under Kyoto Protocol all Annex-I (developed) countries are required to reduce their GHG emissions by 5.2% below their 1990 levels by the first commitment period 2008 - 2012. The CDM allows the Annex-I countries to meet their emission reduction targets by purchasing CERs (certified Emission Reductions) from developing countries. What are CERs? CERs (Certified Emissions Reductions) are "certificates' just like stocks issued by CDM executive board of UNFCCC to the project authority in developing countries. Developed countries buy CERs from developing countries under the CDM process to achieve their emission reduction targets. How to calculate CERs? There are many gases that contribute to the green house effect. But Kyoto Protocol deals with six of them.CERs are awarded based on the global warming potential of the gas. Benefits of CDM, as defined in Article-12 of the Kyoto Protocol, has dual purpose: 1. To assist developing (non Annex-I) countries in achieving sustainable development. 2. To assist developed (Annex-I) countries in meeting their emission targets. All GHG emission reduction projects may not qualify as CDM projects. A project is eligible for CDM benefits if there is a net decrease in green house gas emissions. However, if a project is undertaken because of law to meet legal stipulations then such a project is generally not eligible for CDM benefits. Moreover to quality for CDM, the project must ensure sustainable development for the host country. In India the National CDM Authority (NCDMA) has specified that if a project brings social well being, economic well being, environmental well being and technological well being to the people of India then it ensures sustainable development. The following steps are involved for developing a project under CDM rules: 1. Project Identification and selection. 2. Preparation of Project Design Document (PDD) containing. The project activity and its purpose, the baseline methodology,the period over which the project will create CERs, the monitoring plan for measuring the emission reductions. 3. Host Country Approval (In India it is given by NCDMA under MOEF Govt of India) 4. Validation by Designated Operational Entity (DOE) like DNV, BVQI, TUV etc. Based on the PDD, the DOE evaluates and validates the proposed CDM project. The DOE then issues a validation report and request the CDM executive board for registration of the project based on this report. 5. Registration with CDM Executive Board of UNFCCC. 6. Project Implementation, Monitoring and Reporting 7. Verification by a Designated Operational Entity (DOE) on periodic basis 8. Award of CERs by UNFCCC India's involvement and participation in CDM: India is highly vulnerable to climate change as its economy is highly dependent on climate sensitive sectors like agriculture, forestry etc and also its low lying densely populated coastline is threatened by potential rise of sea level. The Govt of India demonstrated the acceptance of the Kyoto Protocol by confirming its participation in CDM through a cabinet decision in November 2000 and ratified the Kyoto Protocol in August 2002. Not too many Indians are aware that at the heart of the global debate on climate change is an Indian. The noted Indian environmental scientist Dr Rajendra Kumar Pachauri is heading the Intergovernmental Panel on Climate change (IPCC) since April 2002. His tireless work to alert the world about the danger of global warming and climate change has finally won him and his team Nobel Peace Prize in 2007 jointly with former US Vice President Al Gore. While receiving Nobel Peace Prize on 10th December'07 at Oslo. Dr Pachauri mentioned that Climate change is a reality and if proper actions are not initiated then its future implications would be grave and disastrous. Indian Oil's Participation in CDM: Indian Oil being the premier energy company in India has adopted several state of the art cleaner technologies to reduce CO2 emissions by reducing energy consumption, minimizing waste with increased reuse in the refinery operations. With the help of consultants, various schemes have been identified under clean development mechanism (CDM), which are under various stages of approvals. Six schemes have already been approved by the host country and validation by DNV is in progress. The estimated CER earnings would be around 150,000 tons per year. Indian Oil's Digboi Refinery also has taken a lead in this direction as its Crude Oil Preheat Optimization Project in AVU (Atmospheric and Vacuum Distillation Unit) qualifies for CDM benefits. This project is now with UNFCCC for registration.