In 1995, there were 670 million bicycles in China - most used regularly as transportation. The average Chinese family aspired to having "sanshengyixiang" - cleverly translated "three rounds and sound." Or in other words, the symbols of success were a wristwatch, a bicycle, a sewing machine, and a radio.
Since then, as Chinese manufacturing and prosperity have ramped up, and western greed and decadence crept in, Chinese folks were no longer content to ride their bikes. They found themselves wanting to drive a car, and live in the Big City. "To get rich is glorious." (Such a notion has to be troubling to the Communist Party fat cats, huh?) Car ownership doubled, from 4.2 million to 8.9 million, while the bike fleet dropped 35 percent, from 670 million to 435 million.
Which introduced the unwanted byproducts of motor transportation - terrible air pollution and traffic jams of epic proportion. (The article mentions "62 mile, nine-day" traffic jams!)
Now, China seems to be having a minor bike renaissance, fueled mostly by Chinese "hipsters" wanting to be like the hipsters of the West - who ride bikes because it's trendy and fashionable. (Reasons which are so much more valid than the reasons they used to ride bikes - because it's efficient and economical.)