When compensation is not payable?

However, the right to compensation is not payable if:
refusing to take passengers on board are reasonable grounds to such reasons of health, safety requirements, or inadequate travel documentation,
flight was canceled due to exceptional circumstances such as bad weather,
the passenger has been informed of the cancellation at two weeks before the scheduled date of the flight,
offered an alternative flight passengers on the same route at a similar time as the original flight.

If your flight is canceled due to exceptional circumstances and not to the passengers the right to compensation, the carrier, and so must offer him a choice between:
reimbursement of the ticket (for the unused ticket or portion)
alternative means of transport to the destination in the shortest possible time,
transfer up to any date specified by the passenger (if available space).

Compensation is paid in cash, and with the consent of the passenger in the form of a voucher, or services.