The tuple to receive an expression to unpack can have nested tuples, like (a, b, (c, d)) and Python will do the right thing if the expression matches the nesting structure.

Metro.py

metro_areas = [
 ('Tokyo', 'JP', 36.933, (35.689722, 139.691667)),
 ('Delhi NCR', 'IN', 21.935, (28.613889, 77.208889)),
 ('Mexico City', 'MX', 20.142, (19.433333, -99.133333)),
 ('New York-Newark', 'US', 20.104, (40.808611, -74.020386)),
 ('Sao Paulo', 'BR', 19.649, (-23.547778, -46.635833)),
]
print('{:15} | {:^9} | {:^9}'.format('', 'lat.', 'long.'))
fmt = '{:15} | {:9.4f} | {:9.4f}'
for name, cc, pop, (latitude, longitude) in metro_areas: 
 if longitude <= 0: 
 print(fmt.format(name, latitude, longitude))