GD170/21 SOUTH CHINA SEA OFFSHORE CONSTRUCTION BY M/V “CHUANG LI”“HUA XI 5000”“HAI YANG SHI YOU 278” IN AREA BOUNDED BY 21-12N 111-19E，21-12N 111-24E，21-11N 111-24E AND 21-11N 111-19E FROM 3 AUG. 2021 TO 31 MAR. 2022 SIGNAL LIGHTS AND SHAPES WILL BE EXHIBITED ADVISED TO AVOID GUANGDONG MSA CHINA