World Cleanup Day national federations
Global cleanup day coordinated by Let's Do It! World (Tallinn, Estonia). Each country has a national lead organization that runs its federation of local team events.
Countries report participant counts and waste collected; the org publishes country rankings (e.g. % of national population mobilized. Estonia's 4.6% was a national-pride metric). Country leaderboards drive friendly rivalry.
Each country builds a federation of local team leaders who recruit volunteers in their city/town for the synchronized day. Local teams own a site; mutual-support and pre-event coordination happens in-country.
Largest active inter-COUNTRY sustainability competition by participant count. Per-capita ranking (Estonia 4.6%) shows how to fairly compare unequally-sized areas. Useful design pattern for BelongHub leaderboard math.
Others in the same family
Trash Hero World (chapter league)
Swiss-registered nonprofit where each town runs a chapter (resident-led volunteer team) doing weekly cleanups, supported by a global mentor team. Chapters share branding, handbook, methodology.
Klima-Taler
City-branded climate app powered by motiontag that auto-detects walking/cycling/public-transport trips and converts CO2 saved into 'Klima-Taler' coins redeemable at local pools, museums, shops. Each participating city gets its own white-label instance; users join open teams.
STADTRADELN (CITY CYCLING)
Run by Climate Alliance, a 21-day campaign where municipalities sign up to compete on per-capita and absolute cycling kilometers. Mandatory team affiliation; tracked via the CITY CYCLING app GPS or paper log.
2zero Klimathon (Mannheim, Glienicke, Hufeisen-Region, Schleswig-Holstein)
6-week 'Klimathon' run by Berlin-based 2zero (formerly Klimakompass). Each week features 4-6 challenges across themes (mobility, food, energy, consumption, digital, leisure). Mannheim ran as a CoLAB pilot under the EU '100 climate-neutral cities by 2030' Mission starting Jan 2025.
Energy Sparks
Charity-run platform that pulls schools' smart-meter data into an energy-analysis dashboard for pupils and staff, with explicit competition layer.
Cool Block / Cool City Challenge
Block leaders recruit 5-8 neighboring households into a 'Cool Block' that runs a 9-meeting, 5-month program across carbon, water, resilience, livability, and empowerment themes. 'Cool Neighborhood' = ~10 Cool Blocks in geographic proximity.