10 Provision for aircraft noise
| 
 | 
 | 
 | 
 | 
 | 
| (CHF million) | 
 | 2023 | 
 | 2022 | 
| Balance as at 1 January | 
 | 431.3 | 
 | 449.2 | 
| Change in provision for aircraft noise | 
 | –3.5 | 
 | –17.9 | 
| Balance as at 31 December | 
 | 427.8 | 
 | 431.3 | 
| of which current | 
 | 19.4 | 
 | 45.7 | 
| of which non-current | 
 | 408.4 | 
 | 385.6 | 
For information on the reporting of noise-related data in the financial statements in accordance with the Swiss Code of Obligations, see also Reporting of noise-related costs in the financial statements.