The first instrument, the TROPOspheric Monitoring Instrument known as TROPOMI, flies aboard the European Space Agency’s Sentinel-5 Precursor satellite and measures the dry-air column-volume mixing ratio of methane, abbreviated XCH4, across swaths of the planet every day. Because TROPOMI observes the entire atmospheric column between the ground and the satellite, it excels at revealing broad regional patterns: which provinces accumulate the most methane, how those concentrations shift with the seasons, and whether the overall burden is rising or falling over time. What it cannot do, given pixels that span several kilometers, is pinpoint a single leaking pipeline valve or a specific corner of a landfill.

That is where the second instrument comes in. EMIT, the Earth Surface Mineral Dust Source Investigation, was installed on the International Space Station originally to map the minerals in desert dust, but its imaging spectrometer turned out to be remarkably good at something else entirely: detecting the narrow absorption fingerprints that methane plumes leave in reflected sunlight. With spatial resolution fine enough to distinguish individual facilities, EMIT can spot a plume drifting downwind of a gas processing plant or a waste dump and, by modeling how much gas must be present to produce the observed spectral signal, estimate the emission rate in tonnes per hour. The Pakistani team leveraged both instruments in tandem, using TROPOMI to establish the big picture and EMIT to zoom in on the culprits.

The regional picture that emerges from the TROPOMI record is sobering. Between 2019 and 2024, the average atmospheric methane concentration over Pakistan climbed from 1878 ± 13 parts per billion to 1933 ± 14 parts per billion, an increase of roughly 55 parts per billion in just six years. That trajectory mirrors the global rise in methane, which has been accelerating since 2007, but it underscores that a country with rapidly growing energy demand, expanding cities, and a large agricultural sector is tracking at the high end of concern. Methane is more than eighty times more effective than carbon dioxide at trapping heat over a twenty-year horizon, so changes of this magnitude translate into meaningful warming pressure in the near term.

Geographically, the highest methane columns appeared repeatedly over the eastern parts of the country. The Rann of Kutch, the Larkana district, and major urban and industrial centers including Islamabad, Karachi, Lahore, Hyderabad, Multan, Faisalabad, and Gujranwala all registered elevated values. The researchers attribute these hotspots to a combination of natural and anthropogenic activity: dense populations, heavy traffic, industry, agriculture, and in the case of the Rann of Kutch, wetland and seasonal flooding dynamics that foster microbial methane production. The clustering of hotspots over Punjab’s cities and Sindh’s industrial corridor aligns with earlier studies of Pakistan’s air quality, which have ranked several of these cities among the most polluted in the world for particulate matter as well.

Seasonality added another layer to the analysis. Methane concentrations peaked in autumn at 1937 ± 17 parts per billion, followed by summer and then winter. This seasonal rhythm likely reflects a mix of factors, including the timing of rice cultivation and crop residue burning, temperature-driven microbial activity in wetlands and landfills, and atmospheric circulation patterns that either ventilate or trap emissions over the region. The Asian monsoon in particular is known to lift pollution from South Asia into the upper atmosphere, and seasonal wind reversals can redistribute methane across national borders, complicating any attempt to attribute concentrations to sources within a single country.

The most consequential findings, however, came from the EMIT observations, which allowed the team to move from regional averages to named facilities. Between January 2023 and December 2024, the researchers identified and quantified methane plumes originating from three sectors: oil and gas infrastructure, landfills, and electricity generation. The oil and gas sector dominated the tally. The study documented 26 plumes with emission rates exceeding 0.5 tonnes of methane per hour from oil and gas sites, together releasing approximately 78.3 ± 14.7 tonnes of methane every hour. Sustained over a year, emissions of that scale represent millions of tonnes of carbon dioxide-equivalent warming potential, all from a set of facilities that could, in principle, be repaired.

One location stood out above all the rest. Daharki, a town in Sindh province at the heart of Pakistan’s gas-producing region, accounted for the largest number of plumes, with 12 separate detections and total emissions approaching 53.2 ± 9.2 tonnes of methane per hour. In other words, a single cluster of facilities near Daharki was responsible for roughly two-thirds of the oil and gas emissions quantified in the entire study. This pattern echoes what researchers have found in other major producing basins around the world, from the Permian Basin in Texas to offshore platforms in the Gulf of Mexico: a small number of so-called super-emitters, often operating under abnormal process conditions such as equipment malfunctions or venting events, contribute a disproportionate share of total emissions. The implication is that targeted leak detection and repair at a handful of sites can deliver outsized climate benefits.

Landfills emerged as the second major source category, and the detections were unambiguous. The team identified strongly emitting landfill sites releasing between 1 and 5.3 tonnes of methane per hour at Jam Chakro in Karachi, Losar in Rawalpindi, and Lakhodair in Lahore. These are the principal waste disposal sites serving three of Pakistan’s largest cities, and their methane output is the natural consequence of organic waste decomposing anaerobically in massive open dumps. The finding carries a double significance. First, it confirms that unmanaged waste in rapidly urbanizing South Asian cities is a methane source of global relevance, consistent with satellite surveys that have uncovered large landfill emissions worldwide. Second, it points to an opportunity: capturing landfill gas for energy generation, a strategy long discussed in Pakistan, would simultaneously reduce emissions, improve local air quality, and produce usable fuel.

The study arrives at a politically charged moment. Under the Global Methane Pledge, more than 150 countries have committed to cutting global methane emissions by at least 30 percent from 2020 levels by 2030, and Pakistan’s biennial transparency reporting obligations under the UN climate convention require it to account for its emissions with increasing rigor. Until now, the country’s methane inventories have relied heavily on bottom-up estimates and global models that may poorly represent local conditions. By demonstrating that freely available satellite data can both track national trends and expose specific leaking facilities, the researchers have effectively handed Pakistani regulators, and the international community, a verification toolkit. The technical approach, pairing a wide-swath column instrument with a point-source imaging spectrometer, is the same two-tier strategy now being applied in China, India, and the United States, and the Pakistani analysis shows it works even in data-scarce environments. Whether the plumes over Daharki, Jam Chakro, and Lakhodair translate into repairs and policy action remains to be seen, but the era of invisible methane over South Asia is clearly coming to an end.

Subject of Research: Satellite detection and quantification of methane hotspots and emission sources over Pakistan using TROPOMI and EMIT observations

Article Title: Detecting methane hotspots and anomalies from space over Pakistan: analysis using sentinel-5P TROPOMI and EMIT observations

Article References: Mariam, A., Haq, Z. U., & Batool, S. A. (2026). Detecting methane hotspots and anomalies from space over Pakistan: analysis using sentinel-5P TROPOMI and EMIT observations. Air Quality, Atmosphere & Health, 19(10), Article 230. https://doi.org/10.1007/s11869-026-02108-z

Image Credits: AI Generated

DOI: 10.1007/s11869-026-02108-z

Keywords: methane, TROPOMI, EMIT, Pakistan, satellite remote sensing, greenhouse gases, oil and gas emissions, landfills, super-emitters, air quality, climate change, Sentinel-5P