Todays's 'South China Morning Post,' has the Headline:
North Korea’s nuclear test site has collapsed ... and that may be why Kim Jong-un suspended tests
The mountain’s collapse after a fifth blast last fall has led to the creation of a massive ‘chimney’ that could leak radioactive fallout into the air, researchers have found.
I guess its a reasonable question that the SCMP then asks, whether that's the reason for Kim Jong-un's sudden reversal of policy?
The SCMP also points out that the 'chimney' formed by the mountain's collapse may be releasing radioactive substances into the air.
Not a very desirable thing to happen.