help with sql tuning

Dear Team,

This query has been taking along of CPU, is there anyway to further reduce cost ? Thanks in advance !!                                                                                                                           

select COUNT(distinct ABC.APPL_ID) from CS_CASE_INFO ABC,                                                                                                                          

REP_REPOSSESSION_M CDB ,REPO_DISPOSE_DETAILS DAS where queue !=                                                                                                                      

'COMM' and CASE_CLEAR_FLAG = 'N' and DELINQUENT_FLAG = 'Y' and                                                                                                                        

NVL(ABC.REPO_FLAG,'N')='Y' and ACTIVITY ='DATB' and ABC.APPL_ID =                                                                                                                      

CDB.APPL_ID and ABC.CUST_ID= CDB.CUST_ID and ABC.CS_CASE_INFO_ID                                                                                                                       

=CDB.CS_CASE_INFO_ID and DECODE(CDB.DISPOSAL_TYPE,'B','1',CDB.BATCH_ID)                                                                                                                   

in (select DECODE(CDB.DISPOSAL_TYPE,'B','1',BATCH_ID) from