Jaggery gives chai a different flavour, but it still adds sugar to the drink. If you are trying to reduce how sweet your chai is, pay attention to the amount you add and how often you have it. Changing the sweetener while keeping the same sweetness may leave the habit largely intact.
Compare two cups you actually drink
At home you may add sugar with a level spoon. At the canteen, someone may make a whole pot with jaggery and pour you a cup. The spoon, the type of jaggery and the pot size all affect how much ends up in your cup. If you want to compare two home recipes, weigh the sweetener you use for the whole pot and divide by the number of similar cups it makes. Keep the milk and cup size the same for that comparison.
Change one detail at a time
If you like jaggery for its flavour, try a smaller amount and taste the chai before adding more. For a cup bought outside, ask whether it is already sweetened or whether you can add your own. Someone managing diabetes should follow the food advice agreed with their clinician or dietitian, including how sweet drinks fit the rest of the day.
The food-record guide helps you see how often the same drink appears. The sugar claim guide shows what to read if you are comparing packaged drinks.