Rationing access to mud in the Thames

 There's a lot of mud in the Thames, but access to it is limited to when the tide is low (yes, the Thames has tides in the parts that are close enough to the North Sea, including London).  So treasure hunters known as mudlarks must have a permit from the Port of London Authority.

National Geographic has the story:

There’s a 10,000-person wait list to search for riches in London’s Thames
Mudlarking had long been a niche hobby. Then influencers discovered it. 

Twice a day, sections of the River Thames’s shores are exposed by the receding tide, allowing a growing number of mudlarks like Elaine Duigenan to hunt through the mud for treasure.
By Elizabeth Anne Brown

"For decades mudlarks have been granted permission to hunt along the Thames by the Port of London Authority (PLA), which issued permits for up to three years at a time to a small community of hobbyists. But during the pandemic that community grew dramatically, causing the PLA to upend their application process. They recently announced they are capping the total number of permits, each only valid for one year. To accommodate the surge in interest, the agency created a waiting list, which quickly increased to more than 10,000 people and was closed. Active permit holders could not join the list until their current permit was close to expiring, and many veteran mudlarks missed the window. They fear it might take years to get another permit."