Exhibit 21

Subsidiaries of Cabot Corporation (as of September 30, 2019)

Subsidiary	State/Jurisdiction of Incorporation
Cabot Argentina S.A.I.C.	Argentina
Cabot Australasia Pty. Ltd.	Australia
Cabot Australasia Investments Pty. Ltd.	Australia
Cabot Plastics Belgium S.A.	Belgium
Cabot Performance Materials Belgium S.P.R.L.	Belgium
N.V. Norit Belgium	Belgium
Cabot (Bermuda) Ltd.	Bermuda
Cabot Brasil Industria e Comércio Ltda.	Brazil
Cabot Canada Ltd.	Ontario, Canada
Cabot Norit Canada Inc.	New Brunswick, Canada
8755329 Canada, Inc.	Quebec, Canada
Tech Blend Corp.	Quebec, Canada
Cabot Plastics Canada LP	Quebec, Canada
Cabot Plastics Hong Kong Limited	China
Shanghai Cabot Chemical Company Ltd.	China
Cabot Trading (Shanghai) Company Ltd.	China
Cabot (China) Limited	China
Cabot Bluestar Chemical (Jiangxi) Co., Ltd.	China
Cabot Chemical (Tianjin) Co., Ltd.	China
Cabot Performance Products (Tianjin) Co., Ltd.	China
Cabot Risun Chemical (Xingtai) Co., Ltd.	China
Norit China Limited	China
Cabot HengYeCheng Performance Materials (Inner-Mongolia) Company Limited	China
Cabot Performance Materials (Xuzhou) Co., Ltd. (fka NSCC Carbon (Jiangsu) Co., Ltd.)	China
Cabot Colombiana S.A.	Colombia
CS Cabot spol, s.r.o.	Czech Republic
Cabot Czech Holding Company s.r.o.	Czech Republic
Cabot France S.A.S.	France
Cabot Carbone S.A.S.	France
Cabot GmbH	Germany
Cabot Holdings I GmbH	Germany
Cabot Holdings II GmbH	Germany

Subsidiary	State/Jurisdiction of Incorporation
Cabot Aerogel GmbH	Germany
Cabot India Limited	India
P.T. Cabot Indonesia	Indonesia
Cabot Italiana S.p.A.	Italy
Cabot Performance Materials Italy S.r.l	Italy
Cabot Norit Italia S.p.A.	Italy
Aizu Holdings G.K.	Japan
Cabot Asia Kumiai	Japan
Cabot Japan K.K.	Japan
Cabot Supermetals K.K.	Japan
Cabot Norit Japan Co. Ltd.	Japan
Cabot Korea Y.H.	Korea
SIA Cabot Latvia	Latvia
Cabot Luxembourg Holdings S.a.r.l.	Luxembourg
Cabot Luxembourg Investments S.a.r.l.	Luxembourg
Cabot Luxembourg TC S.a.r.l.	Luxembourg
Cabot NHUMO Holdings I S.a.r.l.	Luxembourg
Cabot Asia Sdn. Bhd.	Malaysia
Cabot Elastomer Composites Sdn Bhd.	Malaysia
Cabot Materials Research Sdn Bhd.	Malaysia
Cabot (Malaysia) Sdn. Bhd.	Malaysia
CMHC, Inc.	Mauritius
Cabot Norit Singapore Pte. Ltd.	Singapore
Cabot Singapore Pte. Ltd.	Singapore
Eco-Cabot Activated Carbon Pte. Ltd.	Singapore
Cabot NHUMO Holding S.A.P.I., de C.V.	Mexico
Cabot Specialty Chemicals Mexico S.A.P.I. de C.V.	Mexico
Altamira Carbon, S.A. de C.V.	Mexico
Mexico Reinforcement Materials, S.A.P.I. de C.V.	Mexico
Cabot S.A.	Spain
Cabot International GmbH	Switzerland
Cabot Switzerland GmbH	Switzerland
Cabot B.V.	Netherlands
Cabot Finance B.V.	Netherlands
Cabot Activated Carbon B.V.	Netherlands
Cabot Performance Materials Netherlands B.V.	Netherlands

Subsidiary	State/Jurisdiction of Incorporation
Norit Holding B.V.	Netherlands
Norit International N.V.	Netherlands
Norit Real Estate B.V.	Netherlands
Norit EAPA Holding B.V.	Netherlands
Cabot Norit Nederland B.V.	Netherlands
Cabot Norit Technology B.V.	Netherlands
Cabot Turkey Performans Malzemeleri Anonim Şirketi	Turkey
Black Rose Investments Limited	British Virgin Islands
Dragón Verde Investments Limited	British Virgin Islands
AHB Investments Limited	British Virgin Islands
HDF Investments Limited	British Virgin Islands
Ramaai Holdings Limited	British Virgin Islands
Cabot Performance Products FZE	Dubai, United Arab Emirates
Botsel Limited	United Kingdom (England)
Cabot Carbon Limited	United Kingdom (England)
Cabot G.B. Limited	United Kingdom (England)
Cabot Plastics Limited	United Kingdom (England)
Cabot U.K. Limited	United Kingdom (England)
Cabot UK Holdings Limited	United Kingdom (England)
Cabot UK Holdings II Limited	United Kingdom (England)
Cabot UK Holdings III Limited	United Kingdom (England)
Cabot Performance Materials UK Limited	United Kingdom (England)
Cabot Specialty Fluids North Sea Limited	United Kingdom (Scotland)
Norit (UK) Holding Limited	United Kingdom (Scotland)
Cabot Norit (UK) Limited	United Kingdom (Scotland)
Purton Carbons Limited	United Kingdom (Scotland)
Anglo Dutch Water Carbons Limited	United Kingdom (England)
Cabot Activated Carbon Holdings UK Limited	United Kingdom (England)
Cabot Activated Carbon UK Limited	United Kingdom (England)
Applied NanoStructured Solutions, LLC	Delaware, United States
BCB Company	Delaware, United States
Cabot Asia Investments Corporation	Delaware, United States
Cabot Ceramics, Inc.	Delaware, United States
Cabot Corporation Foundation, Inc.	Massachusetts, United States
Cabot CSC LLC	Delaware, United States
Cabot Europe Limited	Delaware, United States

Subsidiary	State/Jurisdiction of Incorporation
Cabot Holdings LLC	Delaware, United States
Cabot Insurance Co. Ltd. (Vermont)	Vermont, United States
Cabot International Limited	Delaware, United States
Cabot International Capital Corporation	Delaware, United States
Cabot International Services Corporation	Massachusetts, United States
Cabot Specialty Chemicals, Inc.	Delaware, United States
CDE Company	Delaware, United States
Energy Transport Limited LLC	Delaware, United States
Kawecki Chemicals, Inc.	Delaware, United States
Norit Americas Holding Inc.	Delaware, United States
Cabot Norit Americas, Inc.	Georgia, United States
Marshall Mine LLC	Delaware, United States
Cabot Activated Carbon LLC	Delaware, United States
Northeast Boulevard, LLC	Florida, United States
Representaciones 1, 2 y 3 C.A.	Venezuela
Valores Ramaai C.A.	Venezuela