The World Association for the Development of Philately (WADP) and the Universal Postal Union (UPU) jointly conceived and developed the WADP Numbering System - WNS, which was launched on 1 January 2002.

Stamps issued with HK021.10

  1. Hk019.10-80
    Wns Number
    HK019.10
    Country / Post
    Hong Kong (PRC)
    Date of Issue
    July 15, 2010
    Subject
    Biodiversity - Macropodus hongkongensis
  2. Hk020.10-80
    Wns Number
    HK020.10
    Country / Post
    Hong Kong (PRC)
    Date of Issue
    July 15, 2010
    Subject
    Biodiversity - Liuixalus romeri
  3. Hk021.10-80
    Wns Number
    HK021.10
    Country / Post
    Hong Kong (PRC)
    Date of Issue
    July 15, 2010
    Subject
    Biodiversity - Sinopora hongkongensis
  4. Hk022.10-80
    Wns Number
    HK022.10
    Country / Post
    Hong Kong (PRC)
    Date of Issue
    July 15, 2010
    Subject
    Biodiversity - Fukienogomphus choifongae