People who have done their schooling(11th & 12th) from any school in Delhi come under Delhi, otherwise outside Delhi.

GGSIPU has seats reserved for the students from Delhi region (85%) & outside Delhi (15%).

Also, outside Delhi student will need to get a better rank in order to get same college as Delhi student with a lower rank comparatively.

As you are from Chandigarh, you will be treated as Outside Delhi.

All the best.