Q. How can we reduce the seat height of Honda Activa 125?

Why do you want to reduce the height of the seat unless you are not even five feet tall? you may be able to knock off an odd inch or two by scraping or redesigning and replacing the seat, but then your scooter would not be comfortable to drive and is therefore not a neat solution. and what happens when you have to lend your scooter to a close friend or relative ? think about it ! in case you do not see my point, change to a lighter scooter from the competition (there are scores of models available).

From the manufacturer there is no option to adjust the seat height but there are after market methods to do so. The most common method is by slicing off / removing some foam from the seat but its not recommended since the same comfort cannot be expected and also can affect the overall ergonomics of the scooter

There is no adjustment provided to reduce the seat height.Only on e not recommended method is to reduce seat thickness.Hence not advisable.Physically try being seated and roll the scooter forward by feet to check if you can balance comfortably.