| C.L.E.A.N. | Closed Loop Environmental Alliance Network Inc. 
| Others |
| CLEAN | Campbell Local Emergency Action Network
| Others |
| CLEAN | Children Learning Environmental Awareness Now
| Others |
| CLEAN | Christina Ledang Essentials Always Necessary
| Others |
| CLEAN | Citizens League For Environmental Action Now
| Others |
| CLEAN | Citizens Learners Educators Against Neglect
| Others |
| CLEAN | Clean Local Energy Accessible Now
| Others |
| CLEAN | Collection Logistics Efficiency and Notification
| Others |
| CLEAN | Combined Law Enforcement Against Narcotics
| Others |
| CLEAN | Commonwealth Law Enforcement Assistance Network
| Others |
| CLEAN | Community Labor Environmental Action Network
| Others |
| CLEAN | Community Led Environment Action Network
| Others |
| CLEAN | Comprehensive Local Environmental Action Network
| Others |
| CLEAN | Conscious Live Ethical Active and Nourishing
| Others |
| CLEAN | Consumers Lead Emissions Accountability Network
| Others |
| CLEAN | Cryogenic Low-Energy Astrophysics with Noble
| Others |