European shares declined on Tuesday as Brent crude climbed toward $100 a barrel, heightening inflation and recession concerns ahead of the European Central Bank's policy meeting. The STOXX 600 fell 0.6% to about 646 points, while the DAX, CAC 40 and FTSE 100 also retreated. Novartis dropped more than 10%, its steepest one-day decline, after del-desiran failed its primary endpoint in myotonic dystrophy shortly after pelacarsen missed its late-stage clinical goal. Markets broadly expect the ECB to raise borrowing costs by 25 basis points this week. Banking shares fell 1.3%, while energy stocks rose 0.6% as Brent traded near $98.50 a barrel after Iranian threats involving Gulf energy infrastructure.