Key facts of the case:

1. This reference for a preliminary ruling concerns the interpretation of Article 22 of Council Regulation (EC) No 1257/1999 of 17 May 1999 on support for rural development from the European Agricultural Guidance and Guarantee Fund (EAGGF) and amending and repealing certain Regulations (OJ 1999 L 160, p. 80), as amended by Council Regulation (EC) No 1783/2003 of 29 September 2003 (OJ 2003 L 270, p. 70) (‘Regulation No 1257/1999’), and of Article 68 of Commission Regulation (EC) No 817/2004 of 29 April 2004 laying down detailed rules for the application of Regulation (EC) No 1257/1999 (OJ 2004 L 153, p. 30).
2. The reference has been made in the course of proceedings between Mr Nagy, a farmer, and the Mezőgazdasági és Vidékfejlesztési Hivatal (Office for Agriculture and Rural Development; ‘the Hivatal’) concerning a refusal to grant Mr Nagy agri-environmental aid following a check of the information given by him when filing his application for aid.

1. As regards the aid based on Article 22 of Council Regulation (EC) No 1257/1999 of 17 May 1999 on support for rural development from the European Agricultural Guidance and Guarantee Fund (EAGGF) and amending and repealing certain Regulations, as amended by Council Regulation (EC) No 1783/2003 of 29 September 2003, which is subject to a condition relating to the density of livestock, it is permissible under that provision and Article 68 of Commission Regulation (EC) No 817/2004 of 29 April 2004 laying down detailed rules for the application of Council Regulation (EC) No 1257/1999 for the competent authorities to carry out cross-checks with the data from the integrated administration and control system and, in particular, to rely on the data held in the database of a national system for the individual identification and registration of bovine animals, such as the Hungarian system for the individual identification and registration of bovine animals (Egységes Nyilvántartási és Azonosítási Rendszer). 
2. It is permissible under Article 22 of Regulation No 1257/1999, as amended, and Article 68 of Regulation No 817/2004 for the competent authorities, when verifying compliance with the conditions governing eligibility for agri-environmental aid under the former provision, to check only the data held in the database of a national system for the individual identification and registration of bovine animals, such as the Hungarian system for the individual identification and registration of bovine animals, in order to refuse that aid, without necessarily having to carry out other checks.
3. Article 22 of Regulation No 1257/1999, as amended, and Article 68 of Regulation No 817/2004, interpreted in the light of Article 16 of Commission Regulation (EC) No 796/2004 of 21 April 2004 laying down detailed rules for the implementation of cross-compliance, modulation and the integrated administration and control system provided for in Regulation No 1782/2003, place the national authorities – to the extent that, for the purposes of verifying compliance with the conditions governing eligibility for agri-environmental aid under the former provision, which is subject to a condition relating to density of livestock, those authorities check only the data in a national system for the individual identification and registration of bovine animals, such as the Hungarian system for the individual identification and registration of bovine animals – under an obligation to provide information concerning those eligibility conditions which consists in informing the farmer concerned that any animals found not to be correctly identified or registered in that national system are to count as animals found with irregularities liable to have legal consequences, such as a reduction in or exclusion from the aid concerned.