<Tr> <Td> Crossharbour </Td> <Td> Tower Hamlets </Td> <Td> Docklands Light Railway </Td> <Td> </Td> </Tr> <Tr> <Td> Cutty Sark </Td> <Td> Greenwich </Td> <Td> Docklands Light Railway </Td> <Td> Also in zone 3 </Td> </Tr> <Tr> <Td> Dalston Junction </Td> <Td> Hackney </Td> <Td> London Overground </Td> <Td> </Td> </Tr> <Tr> <Td> Dalston Kingsland </Td> <Td> Hackney </Td> <Td> London Overground </Td> <Td> </Td> </Tr>

What is zone 1 and zone 2 in london