Increased emissions of greenhouse gases have altered the global ambient temperature and adversely affected global climatic conditions. The municipal solid waste (MSW) generated by households is considered the third largest anthropogenic source of methane (CH4) emissions, constituting' 11% of all global CH4 emissions. The current study derived total MSW CH4 emission estimates using the IPCC default method (DM), modified triangular method (MTM) and first order decay method (FOD). The estimated CH4 emission was higher for the DM than the other methods, and was comparable to estimates from other studies. This study observed that the net annual emission of CH4 from landfills in India increased from 404 Gg in 1999-2000 to 990 Gg and 1084 Gg in 2011 and 2015, respectively. We also found that CH4 emissions were highly correlated (R2 = 0.8) with the gross state domestic product (GSDP) of states and the gross domestic product (GDP) of the country, which is an indicator of human well-being. The MSW management policy of India needs to be reviewed in a current policy context, as the management and efficient utilization of MSW technologies might help increase the use of CH4 as an energy source and thereby improve its sustainable and cost-effective management.

4. DESCRIPTION (Description shall start from next stage)
Estimation of incinerability of municipal solid waste (MSW) can play a crucial role in the feasibility assessment of waste incineration. A composite indicator called incinerability index or /-Index was developed to estimate the incinerability of MSW incorporating the 3-E concept, i.e. the potential to impact the environment, energy recovery and economy of operation. Eight input parameters that encompass the 3-E concept form the part of the index structure. While some of these parameters may be readily available, a few other input parameters may need to be estimated either experimentally or theoretically. The objective of this study is to effectively demonstrate the estimation of the input parameters, thus facilitating the quantification of incinerability. using/-Index. A theoretical approach to the computation of parameters is introduced as an alternative technique, which can simplify the computation of the index for practical purposes. Following these approaches, the input parameters for MSW generated in South Delhi were estimated and the corresponding/'-Index amounted to 66.1. In comparison with the /-Index of refuse-derived fuel (RDF) which amounted to 80, the incinerability of MSW generated in South Delhi thus quantified was low.
Brief of invention
The increase in greenhouse gas (GHG) emissions has altered the global temperature pattern and created a threat against human health and the environment1’2'3'4'5'6. Methane emitted from landfills is one of the most important contributors to GHGs. Methane (CH4) is regarded as one of the most important GHG because of its global warming potential, which is 28 times higher than that of C027 over 100 years. Over the last few centuries, the concentration of CH4 in the atmosphere has increased rapidly. In a span of 260 years, from 1750 to 2010, the concentration of GHG CH4 in the environment has increased from 700 ppb to 1808 ppb7. The rate of increase observed during the last few decades is 1-2% per year8'9. Along with natural sources, i.e., wetlands, termites, and oceans, which account for 36% of the total CH4/ anthropogenic activities, including the production and burning of fossil fuels, livestock farming, landfills and agriculture, contribute 64% of the total amount of global CH4 emissionslO'11'12'13'14'15. Rapid population growth and development activities have increased the potential CH4 emission level, and it has been estimated that the concentration of GHG CH4 is expected to increase from 6.88 Gt C02-eq, the value recorded in 2010, to 8.59 Gt C02-eq by 202016. The decomposition of municipal solid waste (MSW), i.e., wastes generated from households and residential settingsl7, is considered the third major anthropogenic source of CH4, and it contributes approximately 11% of the total anthropogenic CH4 emissionsl8. Once MSW is disposed into landfills, it undergoes aerobic decomposition, which produces a very small amount of CH4. Afterwards, the anaerobic condition prevails, and due to methanogen activities, the MSW emits CH4 for years, even if the landfill is closedl5. The technologies used

to generate energy from MSW that are prevalent in India, are incineration and biochemical conversionl9'20*21'22'23. In India, only 70-75% of the MSW gets collected, and only 20-25% of it is treated. The technologies involved in MSW management include composting/vermicomposting, recycling and landfilling. So far, only 553 compost and vermicompost plants, 56 bio-methanation plants, 22 refuse derived fuel (RDF) plants and 13 waste-to-energy conversion plants are installed in the country (CPGB 2013-14)24. Many of these schemes have experienced failure due to several issues related to the segregation of waste, low calorific values of the waste, and challenges in the operation and maintenance of the plants (CPCB 2013-14).
Aisian countries are the largest producers of MSW due to their high population densities. The generation of MSW in Asia is predicted to increase up to 1.8 million tons/day by 2025 from the current value of 1 million tons/day25. India, with its huge population and GDP growth rate of 6.7%, is witnessing rapid urbanization and lifestyle changes. The per capita generation rate of MSW in India ranges from 0.2 to 0.5 kg/day26. Presently, approximately 90 million tons of solid waste is generated by the country, which is eight times higher than the amount of solid waste that was generated in 194727. Metropolitan cities have the largest contribution to the generation of waste compared to smaller and less developed cities. At present, India produces 16 Mg C02 equivalent of CH4 per year, and the annual value is expected to reach 20 Mg C02 equivalent by 2020. It is also estimated that CH4 contributes 29% of the total GHG emissions from the country, which is higher than the global average of 15%27'28. Studies suggest that the MSW generated in India mostly consists of a large fraction of organic wastes (40-60%), 3-6% paper waste, and 30-40% ash and fine earth material waste, with smaller fractions of plastics, glass and metal wastes (all <1%). The moisture content of the wastes is 47%, with an average calorific value of 6.8-9.8 MJ/kg and a C/N ratio of 800-1000 Kcal/kg21'23'26.
In India, due to inadequate data availability, a large amount of uncertainty related to MSW management and emissions has been observed, which makes it difficult to estimate the accurate value for the landfill GHG emission potential. The International Panel on Climate Change29 has established a method for the estimation of GHGs emitted from landfills that has been widely used by researchers9'27'30'31.
Studies have been conducted by using different methods, i.e., the stoichiometric method32, default method (DM)9'33, first order decay method (FOD), modified triangular method (MTM)33'34, in situ closed chamber methods35'36 and the landfill gas emission method (Land GEM)27. India is the largest producer of MSW, and landfills are third largest contributors to the total CH4 emission value of the country. To reduce the total CH4 emission value, a strong policy narrative is required in India. The CH4 emitted from landfills can be utilized as a potential source of renewable energy. With the above background, this study aimed to estimate the potential emissions of CH4 from landfills at the national scale, which would support sustainable

management practices in a quickly evolving economy.
Temporal CHA emission estimates with the DM, MTM and FOD
The CH4 emission values calculated using the DM, MTM and FOD are given in Fig. 1. Using the DM and TM, Kumar et al.9 estimated the net annual methane generated in India to be 502.46 Gg and 400.66 Gg, respectively, in the year 19999. However, this estimation was done for Class I and Class II cities. The current study estimates the CH4 emission for the entire country, except for the states of Nagaland, Sikkim, Uttaranchal, Arunachal Pradesh, the Andaman and Nicobar Islands, Chhattisgarh, Goa, Daman and Diu, Lakshadweep and Gujarat ior the year 1999. Out of these, three states were created in November 2000. Gujarat, a major contributor of CH4 emissions, was not included in the study due to an absence of data for the year 1999. Our estimate with the DM, which is 404.86 Gg, used a fraction of degradable organic carbon (DOC) of 0.114 instead of 0.16, the value used by Kumar et al.9, based.on the fractions depicted in the CPCB, 2013. However, when the DOC value of Kumar et oi.9 was used, the DM produced a CH4 emission estimate of 625.05 Gg/Y. This study had different values compared to those of Kumar et o/.9, because it considered the total MSW contribution at a national scale instead of only considering major cities. Similarly, the MTM of this study estimated a lower value, 297.52 Gg/Y, than the triangular method used by Kumar et al.9. The FOD yielded a CH4 emission value of 402.39 Gg/Y for 1999. The total CH4 emission value of three landfill sites in Delhi was calculated by Chakraborty et o/.34, for the year 2009 using the DM (45.7 Gg), MTM (41.4 Gg) and FOD (31.1 Gg)34. However, these estimates were for the MSW received by three landfill sites, not the entire MSW generated in Delhi. The values obtained in our study were 57.35 Gg, 42.14 Gg and 52.15 Gg for the same year using the DM, MTM and FOD methods, respectively, for the entire amount of MSW generated in Delhi rather than the MSW of the three landfill sites considered in Chakraborty et o/.34. Thus, we found that the DM of the IPCC and the FOD estimates of the CH4 emissions agree with estimates from earlier studies.

5. CLAIMS
1. With rapid increases in population and urbanization, uncontrolled municipal solid waste (MSW) is a threat to public health and environmental safety. We explore its generation, treatment, and characteristics of physical/chemical composition and assess the potential of MSW as a renewable energy source.
2. According to claim 1, it is prescribed that it suitable for recovery due to the presence of high organic fraction in the waste and potential waste to energy methods as discussed.
3. According to claim 1, it is prescribed that the presence of methane gas indicated the potential for biogas generation from the waste and its biodegradability under the existing dumping conditions.
4. According to claim 1, it is prescribed that Landfills are considered as cornerstone of solid waste management. Landfill gas (LFG) and leachate are principal outputs from landfills. Methane, occupying significant volume of landfill gas, has considerable potential as a source of energy replacing enormous amounts of fossil fuels currently in use.
5. According to claim 1, it is prescribed that Gas extraction and utilization systems need to be designed and implemented in order to exploit this resource.
6. According to claim 1, it is prescribed that Assessment of economic viability of these systems necessitates estimation of gas released and its energy potential. Gas quantification and energy estimation for municipal solid waste (MSW).
7. According to claim 1, it is prescribed that was carried out using five independent methodologies. A small scale experiment was conducted to monitor the gas generation and the results were compared and analyzed.
8. According to claim 1, it is prescribed that Results show that significant energy can be harnessed from the MSW if requisite LFG management systems are installed.
9. According to claim 1, it is prescribed that the use of methane as an energy source maximizes the extraction of useful resources from landfills, minimizes the global warming and offsets significant amount of fossil fuels.