Task: Question Generation
Input (English): In an attempt to curb air pollution in New Delhi, which gets worst during the winter, a temporary alternate-day travel scheme for cars using the odd- and even-numbered license plates system was announced by Delhi government in December 2015. In addition, trucks will be allowed to enter India's capital only after 11 p.m., two hours later than the existing restriction. The driving restriction scheme is planned to be implemented as a trial from January 1, 2016 for an initial period of 15 days. The restriction will be in force between 8 a.m. and 8 p.m., and traffic will not be restricted on Sundays. Public transportation service will be increased during the restriction period.
Output (English): How long is the initial trial period for New Delhi's driving restriction scheme?