The typical mechanism of deodorant relies on either masking odor or reducing bacterial activity. However, when humidity levels soar, the sheer volume of sweat produced, coupled with the slower evaporation rate, can overwhelm even robust antiperspirants and deodorants. The bacteria break down the components of sweat into volatile compounds that we perceive as odor. In high humidity, this breakdown process is accelerated and amplified, leading to the feeling that your deodorant is no longer working effectively, even if it's applied correctly. This change is often most noticeable in tropical and subtropical climates like much of India, where June marks the onset of the monsoon season or pre-monsoon showers, bringing with them a significant spike in humidity.