Firewall Rule to block traffic between subnets

Can someone give me an example of a simple way to block traffic between 2 subnets on the same router?

Eg:
eth1 202.x.x.x/30 Public IP
eth2 192.168.0.1/24 Nat’d
eth3 10.0.0.1/24 Nat’d

What firewall rules would I use to stop hosts in 192.168.0.0/24 from communicating with 10.0.0.0/24 hosts

Regards,

This will stop the 192.168.0.x net from communicating with the 10.0.0.x net:
/ip firewall filter add chain=forward action=drop src-address=192.168.0.0/24 dst-addresss=10.0.0.0/24
Change the src-address and dst-address around to block the other way if required.

Thanks Tim!