If active and continuous operations are not carried on with respect to a nonconforming use during a continuous period of six months, or for 18 months during a three-year period, for any reason, except where government action impedes access to the premises and there is an intention to abandon such nonconforming use, the building or land where such nonconforming use previously existed shall thereafter be occupied and used only for a conforming use. Intention to abandon shall be evidenced by occupancy for another use, market for another use, etc.