London Mayor Sadiq Khan has taken his environmental initiatives to a whole new level by extending the Ultra Low Emission Zone (ULEZ) to cover an unexpected source of pollution – human flatulence. Londoners are now required to purchase emission credits if they plan on enjoying a plate of beans or a helping of cabbage.

In a groundbreaking move, the mayor’s office declared that the new measures were essential to combat the city’s ever-present air quality issues. “We can no longer turn a blind eye to the methane menace lurking in the city’s stomachs,” announced a spokesperson, who managed to keep a straight face.

Under the expanded ULEZ regulations, citizens caught letting one rip without the proper emission credits could face hefty fines. The city has even introduced a high-tech “Fartometer” to monitor and tax emissions from unsuspecting pedestrians.

Critics argue that this is just another example of Khan’s determination to squeeze every last penny out of Londoners. “First, it was cars; now, it’s our digestive systems. What’s next? Taxing clouds for blocking the sunlight?” lamented a disgruntled resident.

The move has sparked a run on anti-flatulence products, with pharmacies struggling to keep shelves stocked with over-the-counter fart neutralizers and anti-gas pills. Local comedians, however, are having a field day, promising to write off their comedic emissions as tax-deductible.

As Londoners navigate this new olfactory landscape, they are left pondering if their next bowl of chili might just be the reason they’re contributing to air pollution. In the meantime, entrepreneurs are exploring the potential market for personal emission offset credits, with slogans like “Clear the Air, One Fart at a Time.”

Only time will tell if Khan’s gas tax will truly clear London’s skies or if it will just leave a stink in the hearts of the taxpayers.