"Base metals traded mostly lower in May'17 as string of disappointing economic data releases from China raised demand concerns from the world's biggest consumer. Adding fuel to the woes, credit ratings agency Moody's downgraded Chinese sovereign debt from Aa3 to A1 at a time when the mainland nation is trying to heal the economy.
Overall, unfavorable data releases from China along with Moody's downgrade of Chinese sovereign debt hurt the base metals pace in May'17."