I was reading an article about food delivery market and I came across with a term "upstream" and I don't get what that word means. The article says:
Look upstream. China’s online food delivery market is already worth USD 34 billion, with 296 million people using the service in 2018. But instead of engaging in the cash-burning battle currently being waged by delivery platforms Meituan and Ele.me, Panda Selected saw an opportunity to play upstream and think about the challenges that online food delivery poses to restaurants. So ask yourself: what new industry-specific trends are playing out in your industry? How are they creating new challenges for upstream businesses? Can you innovate to serve those players?
Are the upstream businesses those that are trying "to catch a wave" and play on a current trend or is it something else? I didn't find any suitable definition of the term "upstream busines" on the Internet.