 Complete the following phrase:  The government sometimes uses cloud-seeding measures to increase the likelihood of rain showers in the region to clear the air prior to large events, such as prior to the 60th anniversary parade in 2009 as well as to combat drought conditions in the area. More recently, however, the government has increased its usage of such measures as closing factories temporarily and implementing greater restrictions for cars on the road, as in the case of APEC blue and parade blue, short periods during and immediately preceding the 