** TDC falls 5.9 pct to lows not seen sinceNovember 2012 after TeliaSonera and Telenor call off plans to merge their Danish unit
** Merger blocked by the European Commision
** TDC has struggled with increased competition in theDanish market compared with other European countries
** Suggestion from some analysts co will struggle tomaintain its dividend
** Top faller on Stoxx 600 and among most traded byaverage 30-day volumes
** Trader says telco sector being sold on increaseduncertainty surrounding European Commission's position on othermergers. Sector index off 1.9 pct
** Telecom Italia, Telefonica, Cable &Wireless, Vodafone, BT and Bouygues all in top 20 fallers on Stoxx, down 1.2-3 pct
** In Hong Kong, CK Hutchison Holdings off 2.5pct into the close as regulator uncertainty rises. Co has saidit expects to receive approval for its mergers in UK and Italynext year (RM: alasdair.pal.thomsonreuters.com@reuters.net)