| 1.   | I have      reviewed this annual report on Form 20-F of Syngenta  AG; |
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| 2.   | Based on my      knowledge, this report does not contain any untrue statement of a material      fact or omit to state a material fact necessary to make the statements      made, in light of the circumstances under which such statements were made,      not misleading with respect to the period covered by this      report; |
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| 3.   | Based on my      knowledge, the financial statements, and other financial information      included in this report, fairly present in all material respects the      financial condition, results of operations and cash flows of the company      as of, and for, the periods presented in this  report; |
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| 4.   | The company’s      other certifying officer(s) and I are responsible for establishing and      maintaining disclosure controls and procedures (as defined in Exchange Act      Rules 13a-15(e) and 15d-15(e) and internal control over financial      reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for      the company and have: |
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|   | a) | Designed such      disclosure controls and procedures, or caused such disclosure controls and      procedures to be designed under our supervision, to ensure that material      information relating to the company, including its consolidated      subsidiaries, is made known to us by others within those entities,      particularly during the period in which this report is being      prepared; |
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|   | b) | Designed such      internal control over financial reporting, or caused such internal control      over financial reporting to be designed under our supervision, to provide      reasonable assurance regarding the reliability of financial reporting and      the preparation of financial statements for external purposes in      accordance with generally accepted accounting  principles; |
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|   | c) | Evaluated the      effectiveness of the company’s disclosure controls and procedures and      presented in this report our conclusions about the effectiveness of the      disclosure controls and procedures, as of the end of the period covered by      this report based on such evaluation;and |
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|   | d) | Disclosed in      this report any change in the company’s internal control over financial      reporting that occurred during the period covered by the annual report      that has materially affected, or is reasonably likely to materially      affect, the company’s internal control over financial reporting;      and |
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| 5.   | The company’s      other certifying officer(s) and I have disclosed, based on our most recent      evaluation of internal control over financial reporting, to the company’s      auditors and the audit committee of company’s board of directors (or      persons performing the equivalentfunctions): |
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|   | a) | All      significant deficiencies and material weaknesses in the design or      operation of internal controls over financial reporting which are      reasonably likely to adversely affect the company’s ability to record,      process, summarize and report financial information;  and |
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|   | b) | Any fraud,      whether or not material, that involves management or other employees who      have a significant role in the company’s internal controls over financial      reporting. |
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|   | /s/ Michael      Mack        |
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| Name:  | Michael      Mack            |
| Title: | Chief      Executive Officer |

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