New service in Japan to allow mobile users to use other carriers’ networks during outages
(www.straitstimes.com)
Meshtastic is great for this. I have a meshtastic node that is also a 10,000mAh backup phone battery. Just running it as a meshtastic node lasted 50 days on a single charge. And while I've not done another complete drain test on it again, I know for a fact that it lasts over 30 days every single time I charge it.