The 
Shanghai Cooperation Organization (SCO), or 
Shanghai Pact, is a 
Eurasian political, 
economic, and 
security alliance. It is the world's largest regional organisation in 
geographic scope and 
population, covering 
three-fifths of the 
Eurasian continent, 
40% of the human population, and more than 
20% of global GDP.
The 
SCO is the 
successor to the Shanghai Five, a mutual security agreement formed in 
1996 between 
China, 
Kazakhstan, 
Kyrgyzstan, 
Russia, and 
Tajikistan. On 
15 June 2001, the leaders of these nations and 
Uzbekistan met in 
Shanghai to announce a new organisation with deeper political and economic cooperation; the SCO established the following year with the signing of its charter, which entered into force on 
19 September 2003. Its membership has since expanded to eight states, with 
India and 
Pakistan joining on 
9 June 2017. Several countries are engaged as 
observers or 
partners.
The SCO is governed by the 
Heads of State Council (HSC), its supreme decision-making body, which meets once a year. 
Military exercises are also regularly conducted among members to promote cooperation and coordination against terrorism and other external threats, and to maintain regional peace and stability.