The latest nuclear test in North Korea on February 12 has raised concerns about nuclear pollution among residents of North China, with the test site reportedly being less than 100 kilometers from the Jilin border. Fortunately, as yet, Chinese environmental authorities have not found any signs of pollution along the border.

We have to demand that North Korea ensures there is no pollution of Chinese soil or air. This is a red line for North Korea. It is also a guarantee the Chinese government must provide for its own people. If this line is crossed, the Korean Peninsula crisis will turn into China's crisis.

North Korea has been gambling more with each successive nuclear test. The country has been trying to use extreme methods to win a lasting peace, as other countries cannot offer alternative guarantees for strategic security. But this does not mean it will result in North Korea's strategic success.

North Korea is too small to control the strategic risk of owning nuclear weapons. The new arms only put neighboring countries at greater risk and anxiety.

North Korea should not turn itself into a hostage taker, who appears to be safe for now, but is actually the most vulnerable of all in the tricky situation.

As for China, does the test mean a failure of its North Korea policy? Not necessarily. It is unrealistic for some to argue that China has lost the game, saying it should control North Korea and has the power to stop it from developing nuclear weapons.

North Korea has been pursuing an independent diplomatic route for a long time. After the Korean War in the early 1950s, China took a step back, no longer involving itself too deeply in Korean affairs.

China has placed Sino-US relations at a prominent spot since the reform and opening-up policy was launched over three decades ago, while also developing relations with South Korea. China and North Korea still have a special friendship, but it does not equate to an alliance.

All these have resulted in China's limited leverage over North Korea. The Chinese public needs to change its mindset that China is a big brother to North Korea and always has the final say.

China does need to give a stern warning or even punishment to North Korea if it hurts China's interests. But the warning should be one that informs a strategic friend about China's bottom line. China cannot join the camp of the US, South Korea and Japan, by making North Korea China's enemy.

China will adhere to its pursuit of a nuclear-free Korean Peninsula while maintaining its special relationship with North Korea.