Is it obligatory for us—as students in Pakistan—to fast with the people, knowing that their Hilal Sighting Committee includes deviant groups and deliberately opposes the Muslims by a day or two?

If the discrepancy is due to an early start, then fasting is obligatory upon their sighting, based on the Hadith: "Fast upon its sighting and break fast upon its sighting." Fasting becomes obligatory either by the sighting of the crescent by a trustworthy person, or by completing Sha'ban to thirty days.

However, if the discrepancy is due to a delay, then if you yourselves sight the crescent, fasting becomes obligatory for you. If you do not sight it, then it is obligatory for you to complete the count of Sha'ban to thirty days based on the sighting in the country you are in.

It is proper to seek the crescent and follow the guidance of the Companions in this matter, while maintaining a good opinion of the crescent sighting committee, as this is a jurisprudential issue based on principles rooted in scholarly disagreement.