Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
What is the average Area (in km²), when Markatal is less than 0?

### Inputs:
table_name: table, columns: ['Municipality', 'Population', 'Inhabitants per km²', 'Area (in km²)', 'Markatal', 'Island', 'Region']

### Response:
SELECT AVG Area (in km²) FROM table WHERE Markatal < 0