The world's second deepest blue hole (cenote), Taam Ja', located in Chetumal Bay in Mexico, was discovered in 2021 and has just reclaimed the title of the world's deepest blue hole.
Previously, the depth of the underwater Taam Ja' located in Chetumal Bay in Mexico was estimated to be 274 meters.

In December 2023, an oceanographic expedition conducted a probe into the Taam Ja' center. The Conductivity, Temperature, and Depth (CTD) instrument cluster was used to measure the evolution of various physical parameters such as temperature, pressure, and thermoelectric conductivity.
However, when the probe reached 900 feet below the surface, scientists realized that the bottom of the hole was still far away. The measuring device was lowered further to 1,300 feet. And once again, scientists were surprised that the probe was limited by its own operating depth, not because it had reached the bottom.
This means that Taam Ja''s maximum depth is unknown and it is currently definitely the deepest blue hole in the world (so far).
During a recent exploration, scientists also discovered that Taam Ja' is connected to the ocean through a tunnel system.
In fact, cenotes of this type, due to their isolation, often have temperature and salinity conditions that are very different from the rest of the ocean environment. However, at a depth of more than 400 meters in Taam Ja', scientists found that its environmental conditions matched those of the ocean, suggesting a connection to the open ocean.