Answer: Jagirdari system was a system of assignment of land to a person for the purpose of collection of revenue in lieu of cash salary for his duty to the government. With no hereditary rights, it was only for the collection of  land revenue. Mughal Jagirdari system began during the reign of Akbar and in course of time it underwent modifications.

Jagirdari crisis by late 17th century:

By the end of the 17th century, there was a Mughal failure to maintain the Mansabdari-Jagirdari system which also contributed to the decline of the Mughal Empire. 

• Administrative issues: A number of historians stated that the Jagirdari crisis was of an administrative and managerial nature. The lack of good jagirs even in Deccan land was because of Aurangzeb’s decision to keep lucrative jagirs under Khalisa for his campaigns.
• Reduced military might of Jagirdars: Satish Chandra opined that Jagirdari crisis was not because of lack of proportion between increasing number of nobles and corresponding increase of territory. He stated that the tripolar relationship between Jagirdar, Zamindar, & Peasant was disturbed because of reduced military capabilities of jagirdars.
• Number of sawars to be maintained by Jagirdars were reduced during the mid 17th century. This disturbed the military power of Jagirdar due to which he could not perform his functions effectively. This contributed most to the Jagirdari crisis.
• Jama-Hasil discrepancy: There was a difference between Jama (estimated income) and hasil(actual income) due to less capable jagirdars, low quality jagirs, droughts and famines etc.
• Rising number of Jagirdars: Growing number of jagirdars led to imbalance between available resources and rising demand of jagir in the form of salary.
• Owing to wars in Deccan, most paying jagirs were kept in Khalisa to meet the cost of the war. The Jagirdari crisis was exacerbated due to lack of sufficient jagirs for assignment. 
• Corruption and Mismanagement: During Deccan Policy of Aurangzeb, Mughal historian Bhimsen writes about the smallness of the jagirs for Jagirdars. He tells about many of the zamindars and faujdars joining Marathas out of the struggle to get beneficial jagir.
• Eroded polity: According to historian Athar Ali, all the nobles competed for better jagirs, which were increasingly becoming rare due to the influx of nobles (Marathas and Deccanis) from the south. The logical consequence was the erosion in the political structure which was based on jagirdari to a large extent.
• The number of ranks was  totally out of proportion with the actual increase of territory within the period.

The Jagirdari crisis could have been deferred if there was rapid economic development in agricultural and non-agricultural sectors. However, this crisis could not be averted and it constituted one of the significant reasons for the fall of the Mughal Empire.