The announcement of India’s 2070 net-zero target has demonstrated the power of a credible policy signal and changed the course of India’s climate debate. While the Government of India (GoI) has not specified whether this target refers to carbon-dioxide or all greenhouse gases, the announcement has been a watershed moment in India’s climate policy. From questions related to whether and at what pace should India decarbonize its economy, various actors in India are now aligned towards this target. An important contribution to inform India’s net-zero journey has come through various modelling assessments undertaken by India’s institutions and researchers. While a few economy-wide net-zero modelling assessments are available, a comprehensive and integrated picture woven collaboratively by India’s climate experts is conspicuously missing. It is critical to complement quantitative modelling-based assessments with insightful perspectives of experts on India’s climate policy. Together, modelling based quantitative assessments and insightful qualitative perspectives of climate experts would be an instrumental force that will ensure that the country achieves its net-zero target by understanding synergies and trade-offs, harnessing opportunities, and avoiding risks along the way. This collaborative article discusses various aspects of pathways towards India’s net-zero goal to address the gap in literature by looking at broad and inter-related dimensions of ‘national and sub-national perspectives’, ‘sectoral and technological transitions’, and ‘enablers’ needed for India’s transition. While the larger net-zero debate relates to all greenhouse gases, we focus on carbon dioxide in our current effort. The assessment aims to inform not just India’s policy makers and stakeholders, but various researchers, practitioners and governments around the world for them to be better aware of the various aspects of India’s net-zero debate. It weaves the perspectives of experts from 24 institutions across the three broad dimensions to give a comprehensive view of a roadmap towards India’s net-zero future.

Air pollution has large impacts on the Hindu Kush Himalaya (HKH), affecting not just the health of people and ecosystems, but also climate, the cryosphere, monsoon patterns, water availability, agriculture, and incomes (established but incomplete). Although the available data are not comprehensive, they clearly show that the HKH receives significant amounts of air pollution from within and outside of the region, including the Indo-Gangetic Plain (IGP), a region where many rural areas are severely polluted. In addition, the HKH receives trans-boundary pollution from other parts of Asia. This chapter surveys the evidence on regional air pollution and considers options for reducing it, while underlining the need for regional collaboration in mitigation efforts. As described in Chap. 1 , the HKH region is fragile and rapidly changing; while the outcome of the interplay of complex drivers is difficult to predict, it will have major consequences. That holds true for air pollution as well.

The government of Indonesia has pledged to meet ambitious greenhouse gas mitigation goals in its Nationally Determined Contribution as well as reduce water pollution through its water management policies. A set of technologies could conceivably help achieving these goals simultaneously. However, the installation and widespread application of these technologies will require knowledge on how governance affects the implementation of existing policies as well as cooperation across sectors, administrative levels, and stakeholders. This paper integrates key governance variables--involving enforcement capacity, institutional coordination and multi-actor networks--into an analysis of the potential impacts on greenhouse gases and chemical oxygen demand in seven wastewater treatment scenarios for the fish processing industry in Indonesia. The analysis demonstrates that there is an increase of 24% in both CH₄ and CO₂ emissions between 2015 and 2030 in the business-as-usual scenario due to growth in production volumes. Interestingly, in scenarios focusing only on strengthening capacities to enforce national water policies, expected total greenhouse gas emissions are about five times higher than in the business-as-usual in 2030; this is due to growth in CH₄ emissions during the handling and landfilling of sludge, as well as in CO₂ generated from the electricity required for wastewater treatment. In the scenarios where there is significant cooperation across sectors, administrative levels, and stakeholders to integrate climate and water goals, both estimated chemical oxygen demand and CH₄ emissions are considerably lower than in the business-as-usual and the national water policy scenarios.

This article quantifies the environmental, health, and economic co-benefits from the use of solar electricity and heat generation in the Ger area (a sub-district of traditional residences and private houses) in Ulaanbaatar (UB), Mongolia. The quantification of the featured co-benefits is based on calculating emissions reductions from the installation of the solar photovoltaic (PV) and solar water heaters. A user-friendly spreadsheet tool is developed to shed much-needed light on the steps involved in estimating these co-benefits. The tool simulates the hourly electricity and thermal energy generation, taking into account local meteorological conditions, local geographical data, and technical specifications of the solar power and heat generation systems. The tool is then employed to evaluate two intervention scenarios: (1) Installing 100 MW solar electricity, including both rooftop PV and community grids, to reduce the peak-load burden on the grid; (2) Providing solar thermal heaters for 20,000 households to replace the heating load demand from the existing heat only boilers (HOBs) in UB. The modelling results reveal a significant reduction in GHG emissions and fine particulate matter (PM_2.5) (PM that is 2.5 microns or less in diameter) by 311,000 tons and 767 tons, respectively, as well as nearly 6500 disability-adjusted life years (DALYs) and an annual saving of USD 7.7 million for the local economy. The article concludes that the mainstreaming spreadsheet-based estimation tools like the one used in this article into decision-making processes can fill important research gaps (e.g., usability of assessment tools) and help translate co-benefits analyses into action in Mongolia and beyond.

Few challenges pose a greater threat to a healthy planet and people than air pollution and climate change. Over the past three decades, research has demonstrated that integrated solutions to air pollution and climate change can yield co-benefits that support cost-effective, coherent policies. However, research on co-benefits has yet to generate policy responses consistent with this promise. This paper argues that realizing this potential requires more rigorous research on how governance affects the opportunities and incentives to align the interests of government agencies, scientists, and other stakeholders at multiple levels. The article proposes a “One Atmosphere approach” consisting of three building blocks to strengthen that alignment: (1) continually incorporating and strategically timing the introduction of integrated visions; (2) reforming governance arrangements to encourage interagency collaboration and multi-stakeholder cooperation; and (3) supporting integrated visions and institutional cooperation with standardized metrics and assessment methods. This article is also the introduction to the Special Issue ‘One Atmosphere: Integrating Air Pollution and Climate Policy and Governance’, aimed at fostering the multidisciplinary dialogue needed for more integrated air pollution and climate change policies.