In most cases it is very difficult to break a lease without consequence. The lease is a contract and the landlord has the right to enforce that contract. This may involve charging you expensive penalty fees for breach of the agreement. One reason for breaking a lease that you may be able to justify is if you experience constant noise violations that make the space uninhabitable.
Research the local noise ordinance. You can find this information at your local town administration building. The ordinance outlines the hours when loud noise is unlawful in the community---print the ordinance for your records. Examine your local landlord tenant laws as well understand the warrant of habitability when it comes to rental arrangements. In many cases, you must be able to prove that the noise was "dangerous to life, health or safety," according to local landlord-tenant law to deem the space uninhabitable.
Review your rental lease agreement thoroughly. It may have a section regarding noise violations and the required process for reporting complaints to the landlord.
Document all incidents of noise violations in a written journal. Include the specific dates, times and sounds creating the disturbance. Record the noise if it's clearly audible from your apartment. Report the excessive noise to the landlord immediately and keep a record of your contact with the landlord in your journal as well.
Call the local authorities to report major instances of noise violations according to your local ordinance. Get a copy of police reports as official proof of the problem.
Inform your landlord in writing that you wish to end the leasing arrangement without penalty due to the ongoing noise problem that he has not been able to resolve. Provide a move out date and copies of your documentation. In some cases the landlord may take additional steps to fix the problem or offer an apartment transfer to avoid losing you as a tenant.
Prepare to pursue a legal case if the landlord insists on charging you for breaking the lease after you move out. It is not guaranteed that you will win the case, but with a strong paper trail you may be able to prove your case and win.
It is highly suggested that you consult with a lawyer specialising in landlord tenant issues before you contact your landlord in writing.