Congratulations to the 2021 Call for Code Global Challenge winner, Saaf water!

Healthy, usable water is becoming harder to come by as much of it is found to be contaminated. Saaf water is a hardware-software solution that monitors various water quality parameters, allowing for a diverse user base to have the information they need when considering the use of the water that surrounds them. And now, after winning the grand prize, they can expand their solution and assist more communities in need.

The runners up

In addition to the global challenge winner, there were a number of solutions that answered the call to solve the world’s climate change problems with tech. Learn more about the other top teams and their innovative projects below. 

Green Farm

1st runner up
Participant location: China

Community-supported agriculture continues to grow, but consumers face uncertainty around quality, and farmers struggle to reach new markets. Green Farm makes agriculture more sustainable while connecting local producers and consumers. The solution’s VR functionality allows users to view plots of arable land and contract farmers to grow crops. It features a seed marketplace and provides instructions for the entire growing cycle. Once crops have matured, the farmer can ship to the consumer or sell via the app, and the solution ensures traceability and trust throughout via IBM Blockchain. 

Project Scavenger

2nd runner up
Participant location: India

The new normal of remote work has been a significant adjustment for everyone. Many fail to consider the environmental impact that remote work has revealed. The dramatic increase of at-home offices being propped up has meant increased demand to produce devices needed for the workday, which in turn puts stress on the environment that is absorbing increased waste from manufacturers. Project Scavenger is an app that leverages IBM Watson to enable individuals to responsibly dispose of their devices, limiting the amount of waste harming the environment.


3rd runner up
Participant location: Australia

There is no simple and reliable means to display how businesses operate from an ethical, sustainable, and transparent standpoint. Thus, consumers are unable to easily identify and avoid practices that they may disagree with. Honestly is an online browser extension aimed at passing supply chain transparency to consumers. It acts as an assistant throughout the shopping process, alerting users to any bad press on the brand, displaying relevant ratings compiled from external bodies, and benchmarking supply chain data on the selected product against industry standards.


4th runner up
Participant location: Australia

Reducing food waste plays a critical component in tackling climate change as the processing and disposal of food consumes resources such as water, land, and energy, and increases carbon dioxide emissions. Plenti is a mobile application that aims to make the inventory tracking and waste measurement process user-friendly and easy to do at home, allowing consumers to keep track of their groceries, reduce their food waste, and reduce their costs.

Congratulations to the University Challenge winner, Trashtag!


With almost 10 million tons of waste dumped into oceans and natural environments each year, trash has become a severe obstacle in the fight against climate change. Trashtag has designed a decentralized employment model that creates an economic interest in positive ecological action. Through the platform, community members, or “Trashtag Warriors,” target polluted areas for cleanup and submit photos of the newly cleaned area to the app. After each clean up session is validated with AI, community members are awarded with Jobcoin, combining the growing crypto-financial landscape with employment to help protect natural environments.   

View the solutions
by region

Explore the map to learn more about the solutions and the teams who created them.

  • Asia Pacific

  • Europe

  • Greater China

  • India

  • Latin America

  • Middle East and Africa

  • North America