The Civil Aid Service (traditional Chinese: 民眾安全服務隊) or CAS(民安隊) in short is a civil organisation that assist in a variety of auxiliary emergency roles, including search and rescue operations in Hong Kong:
providing support to the government regular emergency forces on counter disaster activities, mountain search and rescue, flood rescue, countryside fire protection duties;
providing crowd control and management services in major public functions;
patrolling country parks and hiking trails and assisting people in need of help;
staging performances to enhance public attention on major campaigns or activities organised by government departments and non-government organisations;
providing training activities and professional services on mountain safety/rescue for government departments and non-government organisations and