why when fruits and vegetables in exported it is packed in bags with holes rather than those without holes?

The holes allow for better air circulation around the food, which keeps it fresher. If there were no holes, it could encourage the growth of organisms and cause rot due to condensation.

Holes causes the "sweat" or condensation from fruits to evaporate. If you don't allow this, the fruits and veggies get all moldy and rotten and would be like a compost pile by the time they reach destination.