Exhibit21.1

Active Subsidiaries of Nalco HoldingCompany

|                                            |  |                            |  |  |  |  |
|--------------------------------------------|--|----------------------------|--|--|--|--|
| CalgonCorporation                          |  | Delaware                   |
| DerypolSA                                  |  | Spain                      |
| Katayama NalcoInc.                         |  | Japan                      |
| Nalco (Shanghai) Trading Co.Ltd.           |  | People's Republic of China |
| NalcoAcquisition One                       |  | United Kingdom             |
| NalcoAcquisition Two Ltd.                  |  | United Kingdom             |
| NalcoAnadolu Kimya Sanayii Ve TicaretAS    |  | Turkey                     |
| Nalco ArgentinaS.R.L.                      |  | Argentina                  |
| Nalco Australia Pty.Ltd.                   |  | Australia                  |
| Nalco BelgiumNV/SA                         |  | Belgium                    |
| Nalco BrasilLtda                           |  | Brazil                     |
| Nalco CanadaCo.                            |  | Canada                     |
| NalcoCompany                               |  | Delaware                   |
| Nalco CompanyLLC                           |  | Delaware                   |
| Nalco de ColombiaLtda                      |  | Colombia                   |
| Nalco DelawareCompany                      |  | Delaware                   |
| Nalco de Mexico, S. de R.L.de C.V.         |  | Mexico                     |
| Nalco DeutschlandGmbH                      |  | Germany                    |
| Nalco Dutch HoldingsB.V.                   |  | Netherlands                |
| Nalco Egypt,Ltd.                           |  | Egypt                      |
| Nalco Energy Services EquatorialGuinea LLC |  | Delaware                   |
| Nalco Energy ServicesLimited               |  | United Kingdom             |
| Nalco EnergyServices, L.P.                 |  | Delaware                   |
| Nalco Espanola,S.A.                        |  | Spain                      |
| Nalco EuropeB.V.                           |  | Netherlands                |
| Nalco Finance HoldingsLLC                  |  | Delaware                   |
| Nalco FinlandOY                            |  | Finland                    |
| NalcoFrance                                |  | France                     |
| Nalco Global HoldingsB.V.                  |  | Netherlands                |
| Nalco GulfLimited                          |  | Jersey                     |
| Nalco HellasS.A.                           |  | Greece                     |
| Nalco HoldingB.V.                          |  | Netherlands                |
| Nalco Holdings GermanyGmbH                 |  | Germany                    |
| Nalco Holdings UKLimited                   |  | United Kingdom             |
| Nalco Hong KongLimited                     |  | Hong Kong                  |
| Nalco Industrial ServicesChile Limitada    |  | Chile                      |
| Nalco IndustrialServices Malaysia SDN BHD  |  | Malaysia                   |
| NalcoIndustrial Services (Su Zhou) Co.     |  | People's Republic ofChina  |
| Nalco International HoldingsB.V.           |  | Netherlands                |
| Nalco Investments U.K.Limited              |  | United Kingdom             |
| Nalco ItaliaSrL                            |  | Italy                      |
| Nalco Japan Co.,Ltd                        |  | Japan                      |
| Nalco Korea,Ltd.                           |  | Korea                      |
| Nalco LeasingCorporation                   |  | Delaware                   |
| NalcoLimited                               |  | United Kingdom             |
| Nalco NetherlandsB.V.                      |  | Netherlands                |
| Nalco New ZealandLimited                   |  | New Zealand                |
| Nalco Oesterreich Gesm.b.H.                |  | Austria                    |
| Nalco Overseas HoldingB.V.                 |  | Netherlands                |
| Nalco Pacific Private,Ltd.                 |  | Singapore                  |
| Nalco ReceivablesLLC                       |  | Delaware                   |
| Nalco Saudi Co.Ltd.                        |  | Saudi Arabia               |
| Nalco ServicesLtd.                         |  | United Kingdom             |
| Nalco Taiwan Co.,Ltd.                      |  | Taiwan                     |
|                                            |

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|                                    |  |                |  |  |  |  |
|------------------------------------|--|----------------|--|--|--|--|
| Nalco Technologie DiversificateSrl |  | Italy          |
| Nalco UK GroupLimited              |  | United Kingdom |
| Nalco UniversalHoldings B.V.       |  | Netherlands    |
| Nalco VenezuelaSCA                 |  | Venezuela      |
| Nalco Worldwide HoldingsB.V.       |  | Netherlands    |
| NalcoZAO                           |  | Russia         |
| NDCLLC                             |  | Delaware       |
| NI Acquisition HoldingsLLC         |  | Delaware       |
| OekophilAG                         |  | Switzerland    |
| Ondeo Nalco IndiaLimited           |  | India          |
| PT NalcoIndonesia                  |  | Indonesia      |
| Treated WaterOutsourcing           |  | Delaware       |
|                                    |

The names ofthe Company's other subsidiaries are omitted because, consideredin the aggregate as a single subsidiary, such subsidiaries would notconstitute a significant subsidiary as of December  31,2005.

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