Causes to terminate the contract
The employer can lawfully terminate the contract if…
(1) The contractor does not begin the work in the proper time or he delays in proceeding the work.
(2) The work is completed after the deadline in the contract or after the reasonable time.
(3) If he paid the compensation for terminating the contract to the contractor.
The end of the contract
If the skill/personal qualification of the contractor is the essence of the contract, and the contractor died or become incapable of carry on working.