To reduce air pollution and ensure blue skies for the parade, half of Beijing's cars were barred from the streets and nearly 10,000 industrial firms in Beijing and in areas near and far – Hebei, Tianjin, Shanxi, Inner Mongolia, Shandong and Henan – suspended or cut production starting on August 20 to cut down on emissions. The factory shut-downs and road closures gave rise to rare instance of clean air, where PM2.5 measurements were below 50, and the lack of traffic jams, and these were welcomed by residents of the capital. Observers noted that the umbrella, which became iconic in Hong Kong during the protests in 2014, were nowhere to be seen despite the blazing heat although commonly used as a shield against the sun in China.