Hi Cosmo,
Love the concept of the jam!
A friend and I made a short prototype for global game jam set during an event called the "Sydney Dust Storm" back in 2009 where the city of Sydney was covered by a dusty red haze. You can see some pictures of the storm here:
https://www.google.com/search?q=%22Sydney+Dust+Storm%22
https://en.wikipedia.org/wiki/2009_Australian_dust_storm
It wasn't great for breathing but was incredibly visually evocative.
When we saw the city jam the idea of building upon what we started and exploring more aspects of this moment in which a familiar city was made unfamiliar was really exciting to us. Would it be okay for us to build upon what we made for global game jam and submit an expanded, more polished version for city jam?
For reference, this is the prototype for global game jam we made
https://globalgamejam.org/2019/games/dust-1