When the landlord won't turn on the heat or the bar downstairs won't turn down the bass, 311 is there. This weekend the city's information hotline took its 100 millionth call. Mayor Michael Bloomberg was at a call center Monday to honor the lucky operator. Sion Nathan got the call Sunday morning for an abandoned vehicle in Borough Park, Brooklyn. While at the center, Bloomberg fielded a call himself-- it was about a garbage pickup. The mayor passed the caller off to another operator.

Bloomberg created 311 in March 2003 and last year took in a record 18.7 million calls.

Top 10 calls since 311 was launched:

Noise (all inquiries): 2,098,288 calls
Heat Complaint - Inadequate Heat: 1,423,786 calls
Bus or Subway Information: 1,241,254 calls
Landlord Complaint - Maintenance: 1,184,753 calls
Parking Violation - Ticket Assistance: 1,042,367 calls
CFC and Freon Removal - Appointment: 975,739 calls
Missing Vehicle - Towed: 845,278 calls
Find a Police Precinct or Police Service Area: 832,062 calls
Alternate Side Parking Information; Status: 713,684 calls
Schedule a Plan Examiner Appointment: 635,628 calls