Tolerance is the phenomenon whereby an individual needs to consume larger amounts of a substance to achieve the same effect that was previously experienced with smaller amounts.
In Dhruv’s case, after years of alcohol consumption, his body has adapted to the presence of alcohol, requiring him to drink more to achieve the same "high" he initially felt with less alcohol. This is a classic example of tolerance, which can develop with prolonged use of substances such as alcohol, drugs, or medications. Over time, the body becomes less responsive to the substance, leading to increased consumption to feel the same effects.