Since 1986, the IUCN has listed the Indian Bison in which category due to its…

Concept: The IUCN Red List ranks species conservation status along a graded threat scale — Least Concern, Near Threatened, Vulnerable, Endangered, Critically Endangered, Extinct in the Wild, and Extinct — based on the rate of population decline, geographic range, and population size, with each higher category signifying a greater risk of extinction.

Application: The Gaur (Bos gaurus), commonly known as the Indian Bison, has been assessed on the IUCN Red List since 1986. Its global population has been declining due to habitat loss, poaching, and diseases transmitted from domestic cattle, and this rate of decline places the species within the threshold that the IUCN defines as Vulnerable — a high, but not yet critical, risk of extinction in the wild.

Cross-check against the other categories:

• Near Threatened describes a milder risk than what the assessed decline in Gaur numbers reflects — the population reduction crosses the higher Vulnerable threshold.

• Critically Endangered describes a far more severe decline, close to total population collapse, which does not match the Gaur's current, comparatively less severe threat level.

• Extinct in the Wild applies only to species that survive solely in captivity or cultivation with no individuals left in their natural habitat, which is not the Gaur's situation.

Since successive IUCN reassessments of the Gaur have kept it within this same band rather than moving it up or down the threat scale, Vulnerable has remained the correct classification since 1986.