“…This section demonstrates a consolidated report of the present review. The review of various HD systems for EO extraction indicates that most of the investigators have used the conventional HD system (40.43%; Amir et al, 2014; Bettaieb et al, 2011; Deepthi et al, 2017; Dev et al, 2010; dos Santos Reis et al, 2020; Fascella et al, 2020; Gill et al, 2014; Khan & Dwivedi, 2019; Mahanta et al, 2020; Mahfud et al, 2017; Manuhara et al, 2018; Milojevic et al, 2008; Mitra et al, 2015; Özcan & Chalchat, 2018; Paul et al, 2019; Perovic et al, 2020; Phuc et al, 2019; Pornpunyapat et al, 2011; Shah et al, 2017; Sintim et al, 2015; Stanojevic et al, 2015; Timung et al, 2016; Tuan et al, 2019; Wang et al, 2008; Wogiatzi et al, 2011; Zheljazkov et al, 2015) for EO extraction, followed by MAHD (27.66%; Drinić et al, 2020; Elyemni et al, 2019; Farhat et al, 2017; Ghazanfari et al, 2020; Golmakani & Rezaei, 2008; Jeyaratnam et al, 2016; Kusuma & Mahfud, 2016, 2018; Megawati et al, 2019; Rezvanpanah et al, 2008; Rihayat et al, 2019; Thakker et al, 2016; Zhang et al, 2020), SAHD (17.02%; Damyeh et al, 2017; Damyeh & Niakousari, 2016; Gavahian et al, 2012, 2015, 2018; Manouchehri et al, 2018; Tunç & Koca, 2019), and OAHD (14.89%; Dupont, 2020; Hilali et al, 2019; Kulturel & Tarhan, 2016; Maiti et al, 2012; Munir et al, 2014; Pesimo, 2017; Ragula et al,…”