I have an “anxiety first aid kit” in my bag for exactly this when I can’t get out to greenspace. I have:

• menthol cough lollies (smell, taste, feel)

• headphones (hear), and earplugs (hear, for when I’m overwhelmed and need some quiet)

• hand warmers (feel, one of my first signs is cold/numb fingers)

• a nostalgic menthol rubbing oil that my mum used to use on my neck and chest whenever I was sick as a kid (smell)

• peppermint oil for when I’m nauseous (smell)

• I wear a ring (feel).

If I resort to headphones, I also use the Balance app and pick one for dealing with anxiety. It gives me something to focus on when someone is telling me what to do.