From green to black, and blue to pink, there is a full rainbow of colors used to describe the different processes used to produce hydrogen.
Green hydrogen, possibly the most important, is made using water and clean/renewable electricity such as solar or wind power.
Blue hydrogen is manufactured using natural gas and steam reforming, which produces carbon dioxide as a by-product. Carbon capture and storage technologies make this form of hydrogen production low-carbon.
Some other colors refer to specific energy sources such as: pink for nuclear and yellow for solar.
To learn more, check out: The hydrogen colour spectrum| National Grid Group