North Korea has been conducting nuclear tests since 2011 when Kim Jong-un took over leadership from his late father.
यस वर्ष उत्तर कोरियाली परमाणु परीक्षणसँंगै त्यँहाका नेता किम जोन उनका बारेमा पनि विश्वको चासो रह्यो।