"China's building a harmonious society," Hassan Bai Runsheng, the mosque's imam, said. "We see a decision like this in the context of creating a harmonious society between Han Chinese and ethnic minority groups."

Even big multinationals are aware of the sensitivities. A Coca-Cola ad features a cute, Babe-like piglet braving mean city streets to get home for the Chinese New Year. But the company shot a second version using pandas to show in Muslim areas.

For those who didn't take such measures, economic losses beckon.

"It is really messing with people's commercial activities," said Paul French, Access Asia's China representative. "It'd be like [in] the second week of December telling people, 'You can run whatever advertising you want, but no images of Father Christmas.'"

French said he's received the edict but, to confuse matters, not everyone's been given the same orders.

"Some people are told 'No live pigs, but you can have animated or cartoon pigs,'" French said. "And some people say 'No pigs whatsoever.'"

To add to the confusion, one agency told NPR that the pig ban had subsequently been relaxed, while others say it's still in place. CCTV refused to grant an interview on the pig ban.

Whatever the situation, the thinking behind the ban is telling.

"The underlying reason goes to the very core of what it is Chinese government views as its patriarchal responsibility to maintain harmony of the entire society," said Tom Doctoroff, China CEO for the JWT advertising agency.

Doctoroff says it can be difficult to predict what might fall foul of the censors.

"We one time had a Pizza Hut ad ... [where] we had this kid standing up on a desk and extolling in fulsome tones the glory of the pizza to attract the other kids," Doctoroff said. "This ad did get censored because the child, the student, the 8-year-old, was viewed as an alternative center of authority."

Other no-nos include using religious figures, for example Buddhist or Taoist monks. And national icons like the Great Wall should be treated with caution. Paul French said edicts — like one issued last year about dragons — should be viewed against the backdrop of China's rising power.

These orders perhaps mirror how the Chinese government would like to see itself: as the protector of minority groups, the guardian of national icons and the ultimate arbiter of harmony. But that role may no longer be possible.

A tune called "the pig song" shows why. It's devoted to describing the pig's dripping snout, its curly tail and its big ears. Posted on the Internet two years ago, it became a surprise hit, it was downloaded a billion times. Even if Beijing had wanted to ban it, modern technology — in the form of the Internet — would have made that impossible.

From the outside, China's government might appear monolithic. But the saga of the pig ban shows how it's struggling with multiculturalism, riddled with insecurity and beholden to commercial pressures, as perhaps never before.