The trend in Germany to ban diesel cars from cities to reduce pollution is a good step and worth considering in Australia.
Such a move could cause grey nomad diesel 4WD owners to make a regional shift with 4WD and caravan. Maybe a high dollar levy on city 4WD owners should be in place.
Any step that can lure people out of the city to a fine regional area should be explored.
Get the downsizers to self-fund out of the city as well and get that disposable money spent in regions.
Shifting to a regional location needs to be made attractive and have tax incentives in place and not just for new arrivals from overseas.