During rainy days, Interval training can’t be done outside, as practice grounds may be waterlogging.
You can prefer doing the same Interval Training on badminton court also. The main accomplishment is, your activity should have a low-high-low intensity workout session for a stipulated time with rest at regular intervals.
On court, choose to do a shadow badminton exercise session for Interval Training. For example, set the time for 6 minutes. Start with a shadow badminton session with moderate speed for the first 2 minutes. The next 2 minutes shadow should be done with considerably more speed than the first 2 minutes. After the 2nd 2 minutes, slow down again to the moderate speed as you started before.
Thus this Interval Training activity on-court involves low-high-low intensity workout.
Doing repetitions depends on how fit you are. If you want to continue with more repetitions, rest adequately before you start the next repetition.